Significance of HPV and cell cycle related proteins in basaloid squamous cell carcinoma of the larynx

Abstract

Objective: To study the significance of HPV and cell cycle related proteins in basaloid squamous cell carcinoma (BSCC) of the larynx. Methods: Twenty-nine cases of laryngeal BSCC from Beijing Tongren Hospital from January 2005 to December 2011 were reviewed. HPV typing by polymerase chain reaction-reverse dot blot (PCR-RDB) and p53, Ki-67, p16, p21 and cyclin D1 expression by immunohistochemistry were performed. The relationship between these indicators, various pathologic parameters (TNM, tumor size, tumor site and lymph node metastasis) and HPV status was analyzed. Results: There were 27 male and 2 female patients. The median age was 62 years. Lymph node metastasis and supraglottic tumor location were slightly higher than that of "usual" SCC, but not statistically significant (P>0.05). HPV DNA was detected in 27.6% (8/29) of the laryngeal BSCC, and all were HPV16. The expression of HPV was not related to age, alcohol consumption, tumor stage and tumor size. p53 was expressed in 31.0%(9/29) of laryngeal BSCC, and these cases were more likely supraglottic and had lymph node metastases (P<0.05). p16 staining was seen in 24.1% (7/29) of laryngeal BSCC, and these cases showed slightly higher rate of lymph node metastasis compared to p16 negative cases. The expression rates of p21 and cyclinD1 were 27.6% (8/29) and 69.0%(20/29), respectively, which were not related to age, tumor size, stage, lymph node metastasis, smoking and drinking. There were only 3 p16+ /HPV+ cases, which showed higher p21 and Ki-67 index compared to the HPV negative group (P<0.05). Conclusion: Some laryngeal BSCC expresses HPV DNA, possibly indicating an association with HPV; but p16 expression is not a reliable indicator for HPV infection.