p16INK4A Expression in Squamous Cell Carcinomas of the Vagina and the Vulva in Tunisian Women

Abstract

<b>Background:</b> The role of p16INK4A expression in uterine cervix cancer is well established. In the remainingfemale lower genital tract cancers, the importance of p16INK4A up-regulation is less clear. In our study, we analyzedthe role of p16INK4A expression and HPV infection in carcinomas of the vulva and the vagina in Tunisian women.Materials and <br/><b>Methods</b>: We conducted a retrospective study of 30 carcinomas including 15 vulvar squamouscell carcinomas (SCCs) and 15 vaginal SCCs. Immunohistochemistry was used to determine p16INK4A expression.HPV detection and typing was by in situ hybridization. <br/><b>Results</b>: p16INK4A expression was detected in 86.7% ofvaginal SCCs with a strong and diffuse immunostaining in 60% of cases, and also in 73.3% of vulvar SCCswith focal immunoreactivity in 53.3% The association between p16INK4A expression and HPV infection wassignificant in vaginal SCCs (p=0.001) but not vulvar SCCs (p>0.05). <br/><b>Conclusions</b>: p16INK4A expression could beused as a useful marker for HPV positivity in vaginal SCCs similar to that described in uterine cervix cancers.However, our data support the presence of 2 different mechanisms for p16INK4A expression in HPV-related andHPV-unrelated vulvar carcinomas.