Introduction of p16INK4a as a surrogate biomarker for HPV in women with invasive cervical cancer in Sudan.

ABSTRACT

BACKGROUND: Cervical cancer is the fourth most common cancer in women worldwide with highest incidence reported in Eastern Africa in 2012. The primary goal of this study was to study the expression of p16INK4a in squamous cell carcinoma (SCC) of the cervix by immunohistochemistry (IHC) and determine relation with clinico-pathological parameters. This study further explored the correlation of p16INK4a immunostaining with another proliferation marker, Ki-67 and to study if human papillomavirus (HPV) IHC can be used as a marker for detection of virus in high-grade dysplasia. METHODS: A total of 90 samples, diagnosed for cervical cancer, were included in the study. Fixed Paraffin Embedded (FFPE) tissue sections were stained with anti-p16INK4a, anti-Ki-67 and anti-HPV antibodies using automated immunohistochemistry platform (ASLink 48-DAKO). RESULTS: Immunohistochemical protein expression of p16INK4a positivity was found to be highest in SCC (92.2%, n = 71) than other HPV tumors (76.9%, n = 10). The majority of cases (97.4%) were p16INK4a positive in the age group 41-60 years. In addition, a statistically significant difference between p16INK4a and HPV was observed among total cervical tumor cases and SCC cases. CONCLUSIONS: As expected staining of invasive cervical cancer with anti-HPV showed rare positivity because HPV heralds active infection in dysplastic lesions and not of frank cervical carcinoma. In contrast, anti-p16INK4a IHC results showed positive correlation in SCC and other cervical tumors.