Sebaceous neoplasms: prevalence of HPV infection and relation to immunohistochemical surrogate markers

Sebaceous neoplasms (SNs) and carcinomas (SCs) represent rare skin adnexal tumours.

To establish the prevalence of HPV in SNs, assess the relationship between HPV, p16 and p53 expression, and further elucidate the carcinogenetic course of SCs.

A total of 113 resected SNs (five sebaceous adenomas, 10 sebaceomas and 98 SCs) from the Near-East were reviewed. Clinical information (age, gender, size and anatomical location), microscopic variables, and expression of several immunohistochemical markers (EMA, CK5/6, p63, p40, AR, p16 and p53) were documented. Cases were evaluated by fluorescently labelled PCR for HPV detection, followed by DNA microarray hybridization for subtype detection.

HPV infection was detected in 9.4% of SNs: 28.6% sebaceous adenomas (HPV-16 and HPV-66), 9.1% sebaceomas (HPV-18) and 8.1% SCs. High-risk HPV types (HPV-16, -18, -52 and -66) constituted 90.9% of HPV infections. Histologically, HPV-positive SCs showed significantly milder cytologic atypia and patchy cellular necrosis. p16 was expressed in SNs irrespective of HPV status (20.0%, 33.3% and 65.5% of HPV-negative sebaceous adenomas, sebaceomas, and SCs, respectively), and p53 was abnormally expressed in 95.5% of HPV-negative SCs and all HPV-positive SCs.

HPV infection is significantly present in benign and malignant SNs. HPV-positive SCs exhibit less cytologic atypia and necrosis than HPV-negative cases. p16 is not a surrogate marker of HPV infection in the SN setting. Further elucidation of various carcinogenic mechanisms in SCs will allow clinicians to single out the various populations at risk, optimize possible preventive strategies and develop targeted therapies.