Prognostic implications of genotyping and p16 immunostaining in HPV-positive tumors of the uterine cervix.

Abstract

Human papillomaviruses (HPVs) are the causative agents of carcinoma of the uterine cervix. A number of HPV genotypes have been associated with cervical cancer and almost all tumors associated with HPV show strong p16 expression. However, there is little information on the possible impact of the HPV genotype and p16 immunostaining on the clinicopathological features or their prognostic value in cervical carcinoma. We evaluated a series of 194 patients with HPV-positive cervical cancers treated at our institution, focusing on the clinicopathological features and the relationship of the HPV genotypes and p16 immunostaining with the prognosis. A single HPV type was identified in 149 (77%) tumors, multiple HPV infection was detected in 30 cases (15%), and undetermined HPV type/s were identified in 15 (8%) carcinomas. HPV 16 and/or 18 were detected in 156 (80%) tumors. p16 was positive in 186 (96%) carcinomas, but eight tumors (4%) were negative for p16 (seven squamous cell carcinomas, one adenocarcinoma); 5/8 caused by HPV 16 and/or 18. Patients with HPV 16 and/or 18 were younger (49 ± 15 vs. 57 ± 17 years, p < 0.01) and more frequently had nonsquamous tumors than patients with other HPV types (24% [37/156] vs. 0% [0/38]; p = 0.01). Neither the HPV type nor multiple infection showed any prognostic impact. Patients with p16-negative tumors showed a significantly worse overall survival than women with p16-positive carcinomas (45 vs. 156 months, p = 0.03), although no significant differences in disease-free survival were observed. In the multivariate analysis, negative p16 immunostaining was associated with a worse overall survival together with advanced FIGO stage and lymph node metastases. In conclusion, the HPV genotype has limited clinical utility and does not seem to have prognostic value in cervical cancer. In contrast, a negative p16 result in patients with HPV-positive tumors is a prognostic marker associated with a poor overall survival.