Possible Factors Related to Phenotype Change from Adenocarcinoma to Squamous Cell Carcinoma

Squamous differentiation/squamous metaplasia is a common feature associated with lung and endometrial adenocarcinomas, but is very rare in the case of colonic and gastric adenocarcinomas. Cases of squamous cell carcinoma and adenosquamous carcinoma (criteria of the Japan Lung Cancer Society) of the lung and endometrial adenocarcinoma with squamous differentiation infected with human papillomavirus (HPV) are frequently seen in Okinawa. A correlation between squamous differentiation and HPV infection was demonstrated (p