Significance of p63 expression in small biopsy specimens of lung cancers

Objective To investigate the importance of p63 and combined examination of p63,CK5/6 and CK7 expression in distinguishing between lung squamous cell carcinomas and adenocarcinomas in transbronchial biopsy specimens or some other small biopsies.Methods Using S-P immunohistochemical methods,we examined the expression of p63,CK5/6,CK7 in 47 cases of small specimens from primary lung cancer,in which histological subtypes were confirmed by further examination of surgically removed specimens.Results The positive rate of p63 was 96%(25/26) in primary lung squamous cell carcinoma.In contrast,adenocarcinomas were 5%(1/21).The positive rates of CK5/6 expression were 81%(21/26) and 10%(2/21) in squamous cell carcinomas and adenocarcinomas of lung,respectively.The positive rates of CK7 expression were 4%(1/26) and 95%(20/21) in squamous cell carcinomas and adenocarcinomas of lung,respectively.Conclusion p63 is an important marker for squamous cell carcinoma.Combined detection of p63,CK5/6 and CK7 is valuable in the differential diagnosis of lung squamous cell carcinoma from adenocarcinoma in small biopsy specimen.