Prognostication of Vulvar cancer based on p14(ARF) status: molecular assessment of transcript and protein

Abstract

Introduction: p14ARF is an important tumor suppressor gene that connects both INK4-cyclin/cdk-Rb and ARF-MDM2-p53 pathways. However, it is poorly investigated in Vulvar Squamous Cell Carcinoma (VSCC). Therefore we aimed to determine the prognostic role of p14ARF in VSCC. Materials and Methods: Immunohistochemistry (IHC) for p14 ARF and p53 and FISH for TP53 were performed in 139 VSCC. HPV genotyping by hybridization method was employed in 100 cases. qRT-PCR for p14ARF and p53 were performed in 16 cases. All results were correlated with clinical-pathological variables. Results: IHC analysis found p14ARF and p53 positivity in 16.4% and 53% cases respectively. p14ARF expression presented significant association with shorter cancer specific survival (P= 0.04), disease-free survival (0.02), presence of perineural invasion (P= 0.037), vascular invasion (P= 0.047) and lymph node metastasis (P= 0.031). Also, p14ARF-positive HPV-negative cases presented the shortest cancer specific survival (P= 0.03) and disease-free survival (P= 0.04). HPV infection was detected in 32.8% of the cases and HPV 16 was the most prevalent type. Viral infection was more prevalent in those poorly differentiated tumors (P= 0.032).qRT-PCR demonstrated that CDKN2A(p14ARF) was overexpressed in tumor samples compared with pared non-cancerous samples (P< 0.001). The opposite relation was seen in TP53 expression evaluation (P< 0.001). FISH demonstrated four cases with deleted TP53(6.3%). Conclusions: p53 and HPV infection did not represent prognostic importance in VSCC. p14ARF represents important marker of poor prognosis. Mainly due to p14ARF‘s relation with lymph node metastasis, the IHC evaluation of this marker appears crucial to establish prognosis and to help determining the most suitable surgical procedure.