Evaluation of Prognostic Significance of the Expression of p53, Cyclin D1, EGFR in Advanced Oral Squamous Cell Carcinoma after Chemoradiation—A Systematic Review

Abstract

The majority of all head and neck tumours are squamous cell carcinomas (SCC). Recent advancements have assisted in producing a body of evidence for the genetic origins of these tumours. Identifying prognostic biomarkers in oral SCC would be of great importance in predicting tumour behaviour and in treatment planning. Many studies have proved that chemotherapy given with radiotherapy leads to better treatment outcomes and overall survival. Biomarkers like p53, cyclin D1, and EGFR, that regulate the cell cycle, have a pivotal role in tumour development and progression. This systematic review aims at analysing the prognostic significance of the expression of p53, cyclin D1, and EGFR in advanced oral SCC after chemoradiation therapy (CRT). A systematic search using predetermined keywords and inclusion/exclusion criteria was conducted in Medline/PubMed, Google Scholar, and other databases to identify relevant articles answering the research question “Does the expressions of p53, cyclin D1, and EGFR have a prognostic significance in recurrent oral SCC treated with chemoradiation?” Literature screening revealed eight articles that were considered for this study. The overexpression of p53, cyclin D1, EGFR was associated with the recurrence of the tumour, and pathologic response can be considered as a prognostic marker. However, the recurrence pattern not only depends on the biomarkers but also on the clinicopathologic factors that play a pivotal role in survival rates among oral cancer patients. The standard management of advanced head and neck SCC has been controversial. It has been concluded that concomitant therapy can result in better treatment outcomes. Clinicians need to scrutinize and evaluate p 53, cyclin D1 and EGFR as a diagnostic parameter for post tumour chemoradiation therapy. Personalised therapy strategies can be created for individual patients using biologically guided tumour characterization, which will enhance quality of life. Thus, the application of more sophisticated technology must be implemented for a better analysis of the tumour.

1. Introduction

The International Agency for Research on Cancer of the World Health Organisation (IARC- WHO) has reported the alarming surge of cancer worldwide day by day [1]. According to the Global Cancer Observatory (GCO), the incidence of oral squamous cell carcinoma (OSCC) in 2020 was around 377,713 cases worldwide, with the highest cases in Asia (65.8%) followed by Europe (17.3%) and North America (7.3%), and the five-year prevalence was 959,248 cases, following the same regional trend. Even though the oral cavity has direct accessibility, early detection of cancer was mostly a failure: therefore, over the past few decades, the survival rates of oral cancer have remained unchanged. According to the GCO predictions, the incidence of OSCC is assumed to increase by up to 40% by 2040. Moreover, advances in molecular biology, genetics, diagnostics, and treatment regimens will lead to earlier diagnosis of cancer, improving mortality and morbidity rates [2].

OSCC represent 80–90% of all oral malignant neoplasm. The factors which are considered to be directly related to the high incidence of OSCC are smoking, betel quid, and tobacco chewing habits [3]. OSCC can develop de novo or as a result of pre-existing potentially malignant diseases [4]. Alteration in cell matrix interaction and cell signalling pathways can lead to increased biological aggressiveness of OSCC [5]. Genetic alterations result in the activation of proto-oncogenes and the inactivation of tumour suppressor genes by deletions, promoter methylation, point mutation, and gene amplification [6]. Genetic alteration causing progression of normal mucosa to cancer is shown in (Figure 1) More than 60 carcinogenic substances have been identified in tobacco smoke [7]. Tobacco contains Nitrosamines 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and N′-Nitrosonornicotine which are also present in both smokeless and inhaled tobacco products. These are considered to be the prime etiologic factors [8]. Approximately 15% to 20% of all oral cancer cases have occurred in patients without the traditional risk factors, as seen in OSCC impacting non-smokers and non-drinkers [9]. One of the etiological factors in such cases is Human Papillomavirus (HPV). A staging design for high-risk HPV-associated cancer of the oropharynx, different from the other etiological factors, was considered in the 8th edition of the American Joint Committee on Cancer [10].

A variety of biological markers have been considered to diagnose and predict the prognosis of oral cancers and potentially malignant lesions. These markers can be divided into genomic markers that include DNA content (ploidy) chromosome aberrations, and changes in expression of oncogenes and tumour suppressor genes; proliferation markers; and differentiation markers that include keratins and carbohydrate antigens [11]. Oral carcinogenesis frequently includes alterations in proto-oncogenes and tumor suppressor genes such as p53, cyclin D1, EGFR, and p16. The mutant p53 protein accumulates in the cell, affecting its biological processes, and its overexpression is thought to be a leading indicator of poor prognosis [12]. The Epithelial Growth Factor Receptor (EGFR) is a cell cycle receptor that manages the cell cycle process and plays an integral part in tumour biology [13]. Cyclin D1 is a protein-encoding CCND1 gene that promotes the progression of the G1-S phase of the cell cycle. Overexpression of EGFR and cyclin D1 is linked to a poor prognosis for the tumour [14].

The clinical outcome of the disease was found to be associated with the biological phenotypes of cancer. Better and more effective treatment modalities can be formulated if such biological characteristics can be identified [15]. A panel of IHC markers can be used for evaluating multiple prognostic molecular biomarkers that identify high-risk OSCC patients [16]. These markers include p53, cyclin D1, and EGFR. However, only a very few studies have been conducted so far in the literature, most of which have been conducted on breast and lung cancer. This systematic review will focus on the research being conducted on cyclin D1, p53, and EGFR, and analyse their prognostic significance in OSCC, which is expected to improve mortality rates.

A focused question was created as specified by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and Participants Exposure Outcomes (PEO) protocol. The research question had been formulated as “Do the expressions of p53, cyclin D1, and EGFR have a prognostic significance in advanced oral SCC treated with chemoradiation?” This systematic review was conducted with the following objectives:

• Prognostic significance of the molecular expressions of p53, cyclin D1, and EGFR in recurrent OSCC treated with chemoradiation.
• To determine if these markers can help in the early detection of cancer and analyse the prognosis of the neoplasm so the treatment modality can be decided accordingly.
• To critically appraise the identified studies.

2. Materials and Methods

The ethical clearance for the study was obtained from King Abdullah International Medical Research Centre [IRB approval number -NRC22R/600/12] before initiating the literature search strategy. The systematic review was carried out in accordance with PRISMA guidelines. A bibliographic search was conducted for research papers published up to May 2022 using PubMed, the Cochrane database, Google Scholar, the National Library of Medicine, Springer Link, and Science Open for the expressions of P53, cyclin D1, and EGFR in recurrent OSCC treated with CRT.

The Medical Subject Headings (MESH) were entered to find the keywords used in the present revision. The following keywords were used to search the electronic databases using the Boolean operators: (“p53”) OR (“cyclinD1”) OR (“EGFR”) AND (“recurrent oral cancer” OR “recurrent oral squamous cell carcinoma” OR “recurrent head and neck cancer” OR “advanced oral squamous cell carcinoma”) AND (“chemoradiation” OR “chemoradiation therapy” OR “radiochemotherapy”). All relevant studies assessing expressions of p53, cyclin D1, and EGFR in recurrent OSCC after chemoradiation were considered for analysis. The systematic review included original research, case-control studies, randomized control trials, case series, and cohort studies in the English language only. This systematic review excluded animal studies, reviews, opinions, and letters.

2.1. Literature Screening Stages

All the data were gathered from PubMed using MESH terms. The stages of the literature screening are depicted in the PRISMA flow chart (Figure 2) in accordance with the criteria for selecting the investigated papers. In the first stage, all article titles were reviewed to eliminate irrelevant original articles, review articles, case reports, and animal studies. Studies were then excluded based on the information from the abstracts. The final screening step was to read the full texts and validate the acceptability of each study based on the inclusion and exclusion criteria. Most of the original publications and studies have demonstrated expressions of molecular markers such as p53, cyclin D1, and EGFR, which could be used as prognostic markers for OSCC and were seen in recurrent tumours.

2.2. Quality Assessment

The selected articles were critically appraised using CASP tools (Critical Appraisal Skills Programme, 2022) and checklists to assess the quality of the methodology, selection criteria and interpretation, as well as a presentation of the results to determine the risk of bias. Relevance, study eligibility criteria, identification, study selection, data collection, study appraisal, synthesis, and findings were also completed. There were no ethical implications to this systematic review.

3. Results

In total, 389 articles were included in primary search, with eight of them meeting the criteria. All the articles used a cohort study design, as shown in Figure 2. From the initial pool of articles, 123 were excluded because they did not meet the required criteria. Following title screening, 227 of the 266 articles were excluded because they were reviews, irrelevant studies, or used treatment modalities other than chemoradiotherapy (chemotherapy, radiotherapy, or surgical resection). The abstracts of the remaining 39 articles were reviewed, and 24 were excluded for reasons such as lack of relevance or lack of focus on the recurrence of OSCC.

Following a review of the full texts, seven of the remaining 15 articles were eliminated. The main reasons for their exclusion were a failure to focus on the prognostic significance of the biomarkers and the inclusion of irrelevant biomarkers. Following the final screening, eight articles were chosen. Since there were not enough publications on the molecular expressions of p53, cyclin D1, and EGFR in recurrent OSCC after chemoradiation, other molecular markers were included. The tables below show the main outcomes and general aspects of the included studies (

Table 1. Experimental research conducted by various authors.

Authors	Objectives	Methodology	Statistical Analysis	Limitations
Lavertu et al., 2001 [17]	To assess the predictive value of p53 and Ki67 expressions for tumour survival and recurrence in cancer patients receiving CRT.	A cohort of 55 patients who were exposed to CRT but were not recruited in the trial, as well as 50 patients from the experimental CRT arm of the randomized trial, were taken into consideration. Radiotherapy was used after chemotherapy. Three IHC analyses—one for p53, one for Ki67, and one as a negative control—were performed.	Fisher’s exact test, Kaplan-Meier and Cox proportional hazards regression analysis were used	Lack of uniformity in IHC techniques in determining the cut off point for the markers. Many other markers need to be explored to have a validated conclusion.
Peisanidhi et al., 2012 [18]	To evaluate immune histochemical expression of p53, p21, p27, cyclin D1, and Ki67 can predict therapeutic response and survival in patients with Oropharyngeal & OSCC treated with preoperative chemoradiation.	111 individuals with an initial diagnosis of Oropharyngeal & OSCC who underwent locoregional resection after neoadjuvant chemoradiotherapy were included. Radiotherapy was used after chemotherapy. Followed by IHC.	Using either v2 tests or Fisher’s exact tests, the relationships between the clinicopathological characteristics of the patients and the expression of the biomarkers were evaluated. Cox proportional hazards regression analysis were also used.	This study did not mention about HPV positive oral cancer
Khan et al., 2014 [19]	To assess the levels of Cyclin-D1 and its prognostic significance with treatment response in oral cancer patients undergoing CRT.	97 locally advanced stage (III, IV) histologically diagnosed OSCC were selected. Radiotherapy was done after chemotherapy followed by IHC.	Kruskal Wallis one way analysis of variance, Kaplan-Meier and logrank test, univariate and multivariate cox proportional hazard analysis were used.	The cause of the cancer was not mentioned i.e., whether it is due to habits (smoking or alcohol) or HPV positivity.
Gupta et al., 2015 [20]	To evaluate the association of EGFR and p53 with survival rate and quality of life in OSCC patients undergoing CRT.	120 patients of locally advanced (III/IV) unresectable oral cancer were included. Radiotherapy was done after chemotherapy followed by IHC.	Cox multivariate regression analysis.	The cause of the cancer was not mentioned i.e., whether it is due to habits (smoking or alcohol) or HPV positivity.
Khan et al., 2015 [21]	To assess the combined expressions of Cyclin-D1, EGFR and p53 and its prognostic significance with treatment response in OSCC patients undergoing CRT.	97 histologically diagnosed OSCC of locally advanced stages (III, IV) were selected. Radiotherapy was done after chemotherapy followed by IHC.	Chi square test, ANOVA, tukey’s post hoc test, Cox’s univariate and multivariate hazard regression analyses were used.	It is essential to use mutation analysis to confirm and validate the IHC overexpression of molecular markers.
Soba et al., 2015 [22]	To investigate how expression of growth promoting (cyclin D1, EGFR, Ki-67) and growth suppressing (p21, p27, p53) tumour markers and CD31 in the primary tumour tissue influenced the outcome of patients with unresectable SCCOP.	In a retrospective research, 74 consecutive patients with stage IV oropharyngeal SCC who received concurrent radio chemotherapy and who were inoperable were processed for p21, p27, p53, cyclin D1, EGFR, Ki-67, and CD31 by IHC. Disease-free survival (DFS) was assessed according to the expression of tumour markers.	Kaplan-Meier and logrank test were used.	The cause of the cancer was not mentioned i.e., whether it is due to habits (smoking or alcohol).
Gupta et al., 2016 [23]	To assess the association of expression of cyclin D1, EGFR and p53 and pattern of recurrence in OSCC patients undergoing CRT.	290 new cases of locally advanced stage oral cancer (III, IV, M0) was histologically diagnosed. Chemotherapy followed by radiotherapy along with IHC were done.	Student’s t-test or one way analysis of variance followed by Tukey’s post hoc test were used.	The findings may further be validated on larger sample size. The co expressions of markers followed by exploring respective gene locus and genetic stability can done.
Solomon et al., 2016 [24]	To observe and quantitate the expression of epithelial growth factor receptor, p53, Bcl-2, cyclin D1 and p16 by the tumour cells and to determine their association with treatment outcomes of the patient.	178 primary locally advanced OSCC patients were selected followed by. Tissue microarray were performed.	Chi square test was done, Poisson proportional and Kaplan-Meier.	Low sample size.

Footnotes: OOSCC = Oral & Oropharyngeal Squamous Cell Carcinoma; SCCOP = Squamous Cell Carcinoma of Oropharynx.

,

Table 2. Prognostic significance of p53.

Author	Biomarker Expression	Biomarker Expression and Clinicopathologic Variables	Pathologic Response	Treatment Response	Tumour Recurrence	Quality of Response
Lavertu et al., 2001 [17]	_	_	_	Not associated.	Predicted overall tumour recurrence (Statistically significant)	_
Perisanidhis et al., 2012 [18]	59% positivity	Low expression of p53 and perineural invasion exhibited significant correlation.	Significantly not associated with pathologic response	No influence.	_	_
Gupta et al., 2015 [20]	75.8% high 24.2 % low	_	_	As the expression increases, response decreases.	_	Significant and inverse correlation with QOL i.e., as expression level increases QOL decreases.
Khan et al., 2015 [21]	85.6%	Significantly associated with nodal status.	_	30.9% complete response, 52.6% partial response& 16.5% no response.	_	_
Soba et al., 2015 [22]	22 out of 59 showed high expression.	-	-	-	-	-
Gupta et al., 2016 [23]	12.1% negative, 15.9% positive & 72.1% strong positive.	Significant association with performance status, primary site, age, histological grade, tumour size & node status.	-	-	Significant association of marker expression with recurrence.	-
Solomon et al., 2016 [24]	111 out of 178 patients were p53 positive (62%).	-	-	-	75% cases exhibited recurrence.	-

,

Table 3. Prognostic significance of cyclin D1.

Author	Biomarker Expression	Biomarker Expression and Clinicopathologic Variables	Pathologic Response	Treatment Response	Tumour Recurrence	Quality of Response
Perisanidhis et al., 2012 [18]	73% positivity	Significantly higher in moderately differentiated tumours.	Pathologic response to neoadjuvant treatment was not being able to assess.	No influence on treatment response.	_	_
Khan et al., 2014 [19]	12. 4% low 64/9% moderate 22.7% high	Lymph node status, clinical stage and tumour size exhibited significant &positive correlation.	_	Overall complete response rate 85.6% and no response is 14.4%.	_	_
Khan et al.,2015 [21]	86.6% positivity	Significant association with nodal status.	_	Strong positive expressions of cyclin D1 exhibited significant association with poor response.	_	_
Soba et al., 2014 [22]	Out of 59 patients, 31, 21 and 7 exhibited low, moderate and high expressions.	-	-	-	--	-
Gupta et al., 2016 [23]	10.7% negative 67.9% positive 21.4% strongly positive	Performance status, histological grade, tumour size, node status, stage and radiological response exhibited significant association.	-	-	Cyclin D1 expression is significantly associated with recurrence.	-
Solomon et al., 2016 [24]	70% positivity	-	-	-	71% recurrence.	-

,

Table 4. Prognostic significance of EGFR.

Author	Biomarker Expression	Biomarker Expression and Clinicopathologic Variables	Pathologic Response	Treatment Response	Tumour Recurrence	Quality of Response
Gupta et al., 2015 [20]	27.5% low 72.5% high	_	_	As expression level increases, response decreases.	_	Significant and inverse correlation between EGFR expression and QOL.
Khan et al., 2015 [21]	92.8%	EGFR did not exhibit significant association.	_	Significant association was observed between strong positive expression of EGFR and partial response.	_	_
Soba et al., 2015 [22]	Out of 59 patients 13, 15 & 31 patients exhibited low, moderate, and high expressions respectively.	_	_	_	_	_
Gupta et al., 2016 [23]	4.6% negative 46.6% positive 49.0% strong positive.	Socioeconomic status, node status, histological grade, stage, radiological response exhibited significant association.	_	_	Significant association with type and site of recurrence.	_
Solomon et al., 2016 [24]	84% positivity.	-	-	-	86% positivity.	-

and

Table 5. Survival analysis and treatment response of the biomarkers.

Authors	Survival Analysis			Treatment Response			Prognostic Evaluation
	DFS	RFS	OS	TR	NR	OR
Lavertu et al., 2001 [17]	_	Overexpressed p53 showed worse RFS	Overexpression of Ki67 showed worse overall survival	No markers predicted tumour response	No markers predicted tumour response	No markers predicted tumour response	Negative association of p53 with recurrence, ki67 worse overall survival
Perisanidhi et al., 2012 (p53, p21, p27, cyclin D1, Ki67) [18]	_	No markers associated with RFS, TNM stage, perineural invasion and pathologic response exhibited significant association.	No markers associated with OS, TNM stage and pathologic response exhibited significant association.	No impact	No impact	No impact	None of the markers were prognostic for overall survival.
Khan et al., 2014 (cyclin D1) [19]	_	_	Positive lymph node and high cyclin D1 has low survival	87.6% CR, 53.6% PR 34%, NR 12.4%	88.7% CR, 49.5% PR 39.2% NR 11.3%	85.6% CR, 29.9% PR 55.7%, NR 14.4%	Positive lymph node status and high Cyclin-D1 expression may be the poor prognostics markers of chemoradiation response with patients of locally advanced OSCC.
Gupta et al., 2015 (EGFR, p53) [20]	89.7%	_	67.5%	CR 53.3% PR 34.2% NR 12.5%	CR 52.5% PR 35.0% NR 12.55%	CR 32.5% PR 52.5 % NR 15.0%	Poor prognosis with low QOL was observed in overexpressed EGFR & p53.
Khan et al., 2015 (p53, cyclin D1 and EGFR) [21]	_	_	Strongly positive forms of cyclin D1 and p53 showed significant & lower survival rates. Additionally, co-expressions of cyclin D1 and EGFR, cyclin D1 and p53, EGFR and p53 showed significant & poor survivals.	_	_	Significant association of strong positive expressions of both p53 & cyclin D1 with poor response was observed.	Cyclin D1 and p53 expression, as well as the co-expression of Cyclin-D1, EGFR and p53, may be used as prognostic indicators in patients with locally advanced OSCC.
Soba et al., 2015 (p21, p27, p53, cyclin D1,EGFR, Ki-67, and CD31) [22]	With better & poor performance status, DFS was 65% and 30% respectively. High expressions of p21, p27, ki67, CD31 & low expressions of p53, cyclin D1 & EGFR has better DFS compared to patients with low expressions of p21,p27, Ki67, CD31 & high expressions of p53, cyclin D1, EGFR. Statistical significance in DFS was observed only in p27.	_	_	_	_		Investigating markers were recognised as significant predictor of DFS.
Gupta et al., 2016 (cyclin D1, p53, EGFR) [23]	_	_	Performance status, primary site, histological grade, tumour size, node status, stage, radiological response and marker expressions exhibited significant correlation.	_	_	_	Increased time to recurrence at primary and distant sites is associated to overexpression of cyclin D1, EGFR, and p53.
Solomon et al., 2016 [24]	EGFR 86%, P53 75%, BCl2 68%, Cyclin D1 71% & P16 55%	_	_	_	_	_	p53 is an independent prognostic marker that could identify patients with a greater risk to develop recurrence. p53, EGFR and p16 have clinical relevance, whereas EGFR and p16 can be valuable for planning treatment protocol. While p53 can serve as a prognostic marker.

Foot notes: DFS = Disease Free Survival; RFS = Recurrence Free Survival; OS = Overall Survival; TR = Tumour Response; NR = Nodal Response; OR = Overall Response, CR = complete response.

).

3.1. Statistical Analysis

Meta-analysis could not be carried out due to the heterogeneity between the studies, i.e., different methodologies, control groups, and observational periods.

3.2. Quality Assessment of the Selected Studies

The CASP tool was used to evaluate the quality of the eight chosen papers. The potential for bias was assessed. To minimize bias, the exposure and outcomes in the selected studies were precisely measured. The risk of bias was low because the inclusion criteria were so strict. However, because the sample size of all the selected papers was limited, the study had to be conducted with a larger sample size to validate the results. Immunohistochemistry was used to assess the level of marker expression in malignancies. Although this method lacks objective quantification, it avoids non-tumour cell contamination and has the advantage of identifying a marker’s positivity and pattern of expression in tissue. However, there is usually little agreement among researchers about the immunohistochemistry results obtained from clinical tumour samples.

The selected studies did not consider factors such as habits (smoking and alcohol) except in one study by Gupta et al. (2016); HPV except by Solomon et al. (2016); and none of the studies included stratified regression or sensitivity analysis to correct or adjust for the confounding factors. Only four of the eight studies calculated the confidence interval, two calculated the risk ratio, and none calculated the absolute risk reduction. The quality of the research was subsequently rated as medium to low. The critical evaluations of the selected articles are provided in the supplementary table (Supplementary Table S1).

Three of the articles reviewed were irrelevant to the current systematic review. The first study concluded that biomarker expression has no effect on survival or chemoradiation response after therapy. The second study found that patients with both P53 and Ki-67 overexpression were nearly three times more likely to be alive with primary site preservation than the rest of the patients. The third study found that cyclin D1, p53, and EGFR were prognostic markers in patients with OSCC.

4. Discussion

Despite the use of concomitant therapies to eradicate OSCC, treatment outcomes have not improved. Factors such as TNM stage, tumour dimension, grading, perineural or vascular invasion, positive lymph nodes, extracapsular extension, nodal location, and size have prognostic significance for local–regional relapse, disease-free survival, and overall survival. To improve the treatment of OSCC, molecular markers were investigated to predict their prognostic values for the selection of the most appropriate treatment modality for better outcomes and survival [23,25].

Most head and neck squamous cell carcinomas (HNSCC) are in advanced stages, and thus require surgery followed by chemoradiotherapy, locoregional radiotherapy, or concurrent chemoradiotherapy. If the surgical procedure is too invasive, chemoradiotherapy is used first. The multimodality approach has improved quality of life in patients with advanced-stage disease, but prognostic factors remain unclear and unresolved. The failure rate after concurrent chemoradiotherapy ranges between 15% and 50% [26]. Despite extensive research on prognostic biomarkers, high-risk factors for recurrence were never identified or resolved in any of the molecular studies [23].

Improved outcomes have resulted from advancements in intensity-modulated radiation therapy or hyper-fractionated accelerated treatment regimens. However, the tumour response to radiotherapy varies between patients. Because one-third of patients do not respond to radiotherapy, the appropriate treatment modality for each patient must be determined based on tumour characteristics to improve survival rates [27]. Further research into molecular biomarkers may reveal biological differences between oral cancers and predict patient outcomes [28].

According to Lavertu et al., a study was conducted on 105 patients treated with chemoradiotherapy to examine p53 and Ki-67 expression as predictors of tumour recurrence, organ preservation, and survival. The final response in the primary site and neck regions was assessed after 6 to 8 weeks, followed by immunohistochemical (IHC) staining. The study showed a negative association between p53 expression and tumour recurrence, and a lower overall survival rate was correlated with Ki-67 expression. Furthermore, the p53-/Ki-67+ combination predicted a lower frequency of tumour recurrence, a lower risk of second primary cancer, and a higher likelihood of organ preservation [22].

According to Perisanidis et al., a study was conducted to assess the therapy response and survival in cancer patients treated with CRT by evaluating the IHC expression of p53, p27, p21, Ki67, and cyclin D1. The study included 111 patients with oral and oropharyngeal SCC (stages II-IV). The margins were evaluated after surgical resection and found to be negative. IHC staining was performed to demonstrate the markers’ prognostic value. The findings revealed that the biomarkers had no effect on the chemoradiation response and were not related to overall survival outcomes. The nodal stage, TNM stage, tumour response, chemoradiation response, and perineural invasion, on the other hand, had a significant association [18].

Khan et al. studied cyclin D1 expression in 97 (stage III-IV) OSCC patients undergoing chemotherapy. The findings revealed that cyclin D1 overexpression and positive lymph node status were poor predictors of treatment response in patients with locally advanced oral cancer. Treatment response decreases as cyclin D1 expression increases. The clinicopathologic factors that show a significant and positive correlation with mean cyclin D1 expressions are tumour size, lymph node status, and clinical stage [19].

Gupta et al. conducted a study to assess the relationship of EGFR and p53 expression with survival, tumour response, and quality of life (QOL) in 120 patients with (stage III-IV) OSCC undergoing CRT. Overexpression of p53 was linked to poor survival, and the overexpression of both p53 and EGFR markers were linked to poor chemoradiation response and low QOL.

Khan et al. conducted a study to assess the combined expressions of p53, cyclin D1, and EGFR as well as their prognostic value in 97 (stages III-IV) oral cancer patients undergoing CRT. The authors discovered that Cyclin-D1 and p53 expression was associated with poor response to treatment, and that co-expression of Cyclin-D1, EGFR, and p53 was associated with poor survival. As a result, they concluded that these biomarkers could be used as prognostic indicators in patients with locally advanced OSCC. Ref. [21] According to Soba et al., a study was conducted to investigate the expression of cyclin D1, EGFR, Ki67, p21, p27, p53, and CD31 in the primary tumour after CRT. They found that patients with high expression of p21, p27, ki-67, and CD31 and low expression of p53, cyclin D1, and EGFR have better disease-free survival [22].

Gupta et al. conducted a study to assess the relationship of cyclin D1, EGFR, and p53 with the pattern of recurrence in OSCC patients undergoing CRT. Increased cyclin D1, EGFR, and p53 levels were found to be associated with tumour recurrence. The researchers concluded that tumours that overexpress cyclin D1, EGFR, and p53 are resistant to CRT and that these markers may serve as predictors of metastasis and locoregional recurrence in OSCC patients [23].

According to Solomon et al., a study was conducted to assess the relationship of EGFR, p53, Bcl-2, p16, and cyclin D1 expression with treatment outcomes in 178 patients with advanced (stage III-IV) OSCC treated with CRT. Only p53 was found to be an independent prognostic marker in this study, identifying patients at higher risk of recurrence. The study concluded that the panel of p53, EGFR, and p16 has clinical relevance, with p53 serving as a prognostic marker and EGFR and p16 being useful for developing personalized treatment protocols [24]. The treatment plan can be created based on the relevant clinical conditions and molecular characteristics of individual cancers. Comprehensive knowledge of the tumour’s biological aggressiveness and customized treatment protocols will significantly affect the cancer patient’s quality of life [24].

4.1. Limitations of this Systematic Review

The aim of this systematic review is to collect data and draw conclusions about the prognostic significance of p53, cyclin D1, and EGFR in recurrent OSCC after chemoradiation. As a result, the quality of the evidence is critical in reaching firm conclusions about the prognostic value of the biomarkers under consideration. There have only been a few studies on the prognostic significance of these biomarkers in head and neck cancer, which is a significant limitation that makes predicting their prognostic significance inconceivable.

4.2. Implications for Practice and Research

The evidence provided in these selected articles can be considered when deciding on an appropriate treatment modality for advanced HNSCC to prevent the recurrence of the tumour. The findings may need to be validated further by studying a larger sample size, marker co-expressions, the evaluation and exploration of respective gene loci, and genetic stability. It is crucial to establish overexpression of IHC markers by mutation analysis. A meaningful course of treatment must be chosen based on additional high-quality evidence if OSCC patients are to have their overall survival rate improve.

5. Conclusions

Various studies on the co-expression of p53, cyclin D1 and EGFR have shown that these markers have a strong association with invasive growth patterns and poor survival. Understanding the more precise and sensitive markers that help with tumour diagnosis, treatment modality selection, monitoring of therapeutic intervention response, early detection of tumour recurrence, and treatment modality prediction should be the focus of deliberate and strategic effort. This systematic review recommends that clinicians should evaluate p53, cyclin D1 and EGFR as a diagnostic parameter for post tumour chemoradiation, which will have a tremendous impact on the quality of life of cancer patients. Consequently, with more knowledge on the biological aggressiveness of the tumours, customised therapy regimens can be developed. In future, advancements in this discipline would make it easier to evaluate biomarkers more efficiently enhancing treatment planning and outcomes and subsequently improving mortality and morbidity rates.