alpha-Amylase in resectable lung cancer.

Biochemical analysis and immunohistochemical techniques support the theory that hyperamylasaemia in lung cancer is due to amylase production in carcinoma cells. The vast majority of amylase-producing carcinomas are adenocarcinomas with amylase isoenzyme similar to the salivary type. This prospective study assesses alpha-amylase expression in resectable lung cancer. Seventy four patients with resectable lung cancer were studied. Amylase activity in tumour tissue was analysed and isoamylase identification performed. Immunohistochemical analysis was performed using a polyclonal rabbit antibody against human salivary amylase. Hyperamylasaemia occurred in 13 out of 70 patients. Increased amylase activity in tumour tissue was found in 10 out of 52 cases, of which only two were associated with hyperamylasaemia. With the exception of one large cell carcinoma and one squamous cell carcinoma, the tumours were adenocarcinomas. Immunohistochemical analysis revealed amylase expression in seven adenocarcinomas and two adenosquamous carcinomas. In conclusion, immunohistochemical amylase expression was restricted to carcinomas with adenomatous differentiation. Biochemical analysis confirmed amylase production in 5 of 7 cases examined, the tissue amylase isoenzymes being of salivary type. However, hyperamylasaemia and a slightly increased amylase activity in tumour tissue may be caused by factors other than amylase-producing carcinoma cells.