Evaluation of PD-L1 Expression and HPV Genotyping in Anal Squamous Cell Carcinoma
Anja Wessely, Markus V. Heppt, Claudia Kammerbauer, Theresa Steeb, Thomas Kirchner, Michael J. Flaig, Lars E. French, Carola Berking, Elisa Schmoeckel, Markus Reinholz
Abstract
Anal squamous cell carcinoma (SCC) is a rare cancer with increasing incidence. Infection with high-risk human papillomavirus (HPV) subtypes is the major cause for its development. We retrospectively analyzed tumor samples from 54 anal SCC patients for infection with a panel of 32 HPV subtypes in a PCR-based approach, determined the PD-L1 expression status, and correlated the findings with the clinical data and the survival of the patients. Forty-two patients (77.8%) were HPV-positive and harbored at least one carcinogenic HPV subtype. HPV16 was the most frequently detected (n = 39, 72.2%). Four patients were infected with multiple HPV subtypes. HPV infection was significantly more often detected in female than in male patients (90.3% vs. 60.9%, p = 0.018). Patients with PD-L1 positive tumors showed a significantly better median overall survival (OS) compared with patients with PD-L1 negative tumors (69.3 vs. 28.3 months, p = 0.006). The median OS was significantly different among the distinct tumor stages (p = 0.029). Sex, grade of differentiation, and HPV infection status did not influence the median OS. Furthermore, HPV infection status and PD-L1 expression were not correlated. A multivariate Cox regression analysis revealed that PD-L1 expression status was an independent prognostic marker for survival (p = 0.012).