HUMAN-PAPILLOMAVIRUS DNA IN ADENOSQUAMOUS CARCINOMA OF THE LUNG

Aim-To investigate the presence of human papillomavirus (HPV) DNA in a denosquamous carcinoma of the lung-which is relatively common in Okina wa but not in mainland Japan-and examine its histological features. Me thods-Of 207 cases where primary lung cancers were surgically removed between January 1995 and June 1997 in Okinawa, 23 were adenosquamous c arcinoma. HPV was detected by non-isotopic in situ hybridisation (NISH ) and polymerase chain reaction (PCR) amplification with primers speci fic for E6 and E7 regions of the HPV genome. PCR products were analyse d by Southern blotting. Immunohistochemical determination of high mole cular weight cytokeratin (HMC) and involucrin was also carried out. Re sults-18 cases were positive for HPV DNA by PCR and MSH. HPV types 6, 11, 16, and 18 were found. Seven cases were dual positive for differen t types of HPV. Using NISH, HPV was also found in the squamous cell co mponents and in neighbouring enlarged adenocarcinoma cells. The HMC an d involucrin were demonstrated immunohistochemically in the same areas . Conclusions-HPV DNA was found in a high proportion (78.3%) of adenos quamous carcinomas in Okinawa, a region where HPV has previously been shown to be prevalent in squamous cell carcinoma of the lung. The aden ocarcinoma cells adjacent to the squamous cell carcinoma component wer e enlarged and positive for HPV, HMC, and involucrin. This is thought to indicate the transition from adenocarcinoma to squamous cell carcin oma.