Clinicopathological Parameters and Biomarker Profile in a Cohort of Patients With Head and Neck Squamous Cell Carcinoma (HNSCC).

Introduction:  Squamous cell carcinoma (SCC) is the most common malignancy of the head and neck region, commonly termed as head and neck squamous cell carcinoma (HNSCC). Data related to biomarker expression in HNSCC are scarcely available, especially in our population. This study aimed to evaluate the association of immunohistochemical (IHC) expression of p16, epidermal growth factor receptor (EGFR), p27, and p53 in HNSCC with clinical and pathological parameters.

Methods:  This retrospective cross-sectional study was conducted at the Department of Histopathology, Liaquat National Hospital, Karachi, Pakistan from February 2017 to January 2022. A total of 308 cases of HNSCC with upfront surgical resection were included in the study. IHC analysis was performed for EGFR, p16, p27, and p53, and association with clinicopathological parameters was sought.

Results:  p16, EGFR, and p53 positivity were noted in 22.1%, 18.8%, and 66.2% cases, respectively, whereas loss of p27 expression was seen in 14.3% cases of HNSCC. A significant association of p16 expression was observed with age, tumor size, tumor site, nodal metastasis, extranodal extension (ENE), and perineural invasion (PNI). Cases aged over 50 years were more significantly associated with positive p16. Similarly, cases with oral cavity SCC were more significantly associated with positive p16. HNSCC with larger tumor size, the presence of nodal metastasis, and ENE and PNI were associated with negative p16 expression. Similarly, a significant association of EGFR expression was observed with age, tumor size, tumor site, histological subtype, histological differentiation, nodal metastasis, ENE, and PNI (p < 0.05). Cases of HNSCC with age less than 50 years were associated with positive EGFR expression. Similarly, oral cavity and lip SCCs were associated with positive EGFR expression compared with other sites. Moreover, positive EGFR expression was significantly associated with nodal metastasis, ENE, moderate histological differentiation, and the presence of PNI. Loss of p27 expression was significantly associated with nodal stage and ENE; low nodal stage and absence of ENE were associated with p27 loss of expression, whereas no significant association was seen with other pathological parameters. Alternatively, a significant association of mutant-type p53 expression was noted with gender, nodal stage, and histological subtype. Females with HNSCC show a higher frequency of mutant-type p53 expression than males. Moreover, higher nodal stage (N2b and higher) and non-keratinizing SCCs were significantly associated with mutant-type p53 expression.

Conclusion:  Our study found a high expression of EGFR and mutant-type p53 expression in HNSCC. Conversely, p16 expression and loss of p27 expression were low. Moreover, EGFR and mutant-type p53 expression were associated with poor pathological parameters, whereas p16 expression was associated with better histological features.