Prognostic Significance of HER-2 and p53 Expression in Gallbladder Carcinoma in North Indian Patients.

BACKGROUND/OBJECTIVE: Proto-oncogenes (HER-2) and tumor suppressor genes (p53) are commonly deregulated in gallbladder cancer (GBC). Available literature discloses skewed data from endemic Asian countries, especially north India. This study evaluates the prognostic significance of HER-2 and p53 in GBC patients from two major hospitals.

METHODS: Sixty resectable tumor and control specimens were prospectively collected from December 2012 to January 2016. Immunohistochemical staining was done using monoclonal antibodies to semiquantitatively evaluate HER-2 and p53 protein expression. The criterion for HER-2 positivity was set at >30% tumor cells showing complete, membranous staining while p53 positivity was established at <50% tumor cells showing complete nuclear staining. Clinicopathological correlations were drawn with major clinical outcomes.

RESULTS: It was observed that 36.67% (22/60) tumor cases and 5% (3/60) control cases showed strong HER-2 overexpression significantly correlating with sex, T-stage, nodal spread and distant metastasis (p < 0.05), while 33.3% (20/60) positivity was observed for p53 in tumor cases and 1.7% (1/60) in control cases. Multivariate analysis showed HER-2 (p = 0.04; hazard ratio: 2.36; 95% confidence interval: 1.04-5.33) and p53 (p = 0.03; hazard ratio: 5.63; 95% confidence interval: 1.21-26.26) expression to be independent prognostic factors.

CONCLUSION: Our study thus suggests the plausible role of HER-2 and p53 expression in worse prognosis of GBC in a north Indian population.