Expression of alpha-amylase in human lung cancers.

Thirty-three human lung tumors were studied for the expression of alpha-amylase by immunohistochemical and Northern blot analyses. Twenty of them were adenocarcinomas, among which 17 proved to be adequate for mRNA analyses and were, except for two, amylase mRNA producers. Seven were squamous cell carcinomas, none of which produced amylase. The remaining six consisted of two undifferentiated small cell carcinomas, and one each of undifferentiated large cell carcinoma, carcinoid tumor, mucoepidermoid carcinoma, and metastatic lung cancer; the mucoepidermoid carcinoma proved to be an amylase producer. These observations strongly suggest that among lung cancers, the production of alpha-amylase is a property commonly associated with adenocarcinomas and can be used for distinguishing cell types. Histogenesis and carcinogenesis in lung cells are discussed in connection with the cells that produce amylase.