P4 Gupta et al.

Expression and Interrelationship of p16, p53 and EGFR (by Immunohistochemistry) in Oropharyngeal Squamous Cell Carcinomas (OPSCC) and Prognostic correlation.

Gurudutt Gupta, Sunil Pasricha, Anila Sharma, Rakesh Gupta,  Jatin S Gandhi, Garima Durga, Meenakshi Kamboj, Anurag Mehta

Department of Pathology, Rajiv Gandhi Cancer Institute & RC. Rohini Sector 5. Delhi. India.

Background Expression of p16 by IHC is a reliable surrogate marker for HPV associated OPSCC and predicts good prognosis. EGFR over expression has been reported in 46–72% of OPSCC. p53 over expression has shown to be associated with smoking, poor prognosis and risk of second primary malignancy(SPM).

Methods One hundred cases(100) of OPSCC in two years were evaluated for grade, p53, EGFR and p16 IHC expression. The follow-up was done for outcome evaluation.

Results In our study 95% were males and 67 % were tobacco users. p16, p53 and EGFR positivity rates were 25%, 53% and 50% respectively. p16 positivity was associated with EGFR positivity and p53 negativity, although not statistically significant. Association of p53 expression with nodal disease & p16 expression with  bilateral (N2C) and bulky (N3) nodal metastasis showed statistically significant correlation. p16 positivity was associated with decreased DFS (p value: 0.046) in-comparison to p16 negative tumors, which was unusual.

Conclusion The biological behavior of p16 positive tumors can be altered by tobacco use. More than 50% of the p16 positive cases were smokers/tobacco users and 44% were associated with p53 positivity. Others factors, which can modify the biological behavior are close surgical margins, higher stage on presentation or other associated co-morbidities.