IMMUNOHISTOCHEMICAL EXPRESSION OF p16 AND p53 IN HEAD & NECK SQUAMOUS CELL CARCINOMA; RELATION WITH HISTOCHEMICAL & CLINICAL PARAMETERS

Abstract

Background: Uncontrolled cell proliferation due to irregularities in cell cycle checkpoints, leads to a disastrous condition termed ‘Cancer’. This is an interwoven process of proto-oncogenes and tumour suppressor genes. Disruption in tumor’s immune microdomains lead to carcinogenesis. It is one of the major health burdens in the developing countries of Asia including Pakistan. Head and neck squamous cell carcinoma is increasing in South-Asia on account of frequent tobacco consumption and areca nut chewing. Majority of these carcinomas are of squamous cell type.

Objective: To evaluate the immunohistochemical expression of p16 and p53 in head & neck squamous cell carcinoma and its relation with histochemical & clinical parameters.

 Methodology: 138 patients with head and neck carcinoma were included in the study. Haematoxylin and eosin staining was done on sections and evaluated by two trained histopathologists. Clinico-pathologic & risk factors were recorded. Immunohistochemistry for p53 and p16 was performed. Data was analysed using SPSS version 25.0

Results: Out of total 138 cases of head and neck squamous cell carcinoma p16 was positive in 25 (18.11%), equivocal in 34 (24.6%) and negative in 79 (57.2%) instances. Besides, 96 (69.6%) tumors were positive for p53 and 42 (30.4%) were negative. On basis of intensity, strong p53 expression was noted in 31.90% cases while 29% & 8.70% cases revealed intermediate & weak staining respectively. No significant association of p16 expression was noted with histopathologic parameters. However, purposeful relationship was noted between p53 and clinical history of smoking as well as pan intake. Significant association of p53 expression was also noted with T-category, extra nodal extension, lympho-vascular invasion and perineural invasion.

Conclusion: Our study revealed no association of p16 with any histopathologic factors. However, smoking & pan intake had notable relation. Significant relationship was established between p53 and various studied parameters (history of smoking and pan usage, extranodal extension, lymphovascular invasion & perineural invasion). p53 turns out to be a serviceable prognostic marker. The results for both of these markers indicate need for a larger scale study in our population. It also hints on sub-grouping the head and neck squamous cell carcinomas on the grounds of etiology & molecular studies. Dividing these cases based on their innate biology and mutational topography can provide rationale for customised treatment.

Keywords: Cancer, Immunohistochemical, Head And Neck Squamous Cell Carcinomas HNSCC, Tumor Stage, Nodal Stage, P53, P16, Tobacco.