Acid phosphatase activity in carcinoma of the bronchus.

, , 472-477. Two cases are presented in which an undifferentiated small-cell carcinoma of the bronchus was associated with a considerably raised serum tartrate-labile acid phosphatase concentration. In neither case was there any evidence of a carcinoma of the prostate which, with a few rare exceptions, is the only condition associated with such increased enzyme activity. A survey of acid phosphatase concentrations in 30 other male patients with carcinoma of the bronchus showed that five patients had a raised total acid phosphatase concentration, but only one patient had a raised tartrate-labile acid phosphatase concentration. When the histological type was taken into account, elevated total acid phosphatase concentrations were associated with squamous-cell and adenocarcinoma but not with undifferentiated, small-cell carcinoma. Raised tartrate-labile acid phosphatase concentrations were associated only with squamous-cell carcinoma, in contradistinction to the two individual cases reported. In no group was there any correlation between acid and alkaline phosphatase concentrations. Histological studies in one of our patients showed little tissue acid phosphatase staining in the primary tumours but intense staining in the cytoplasm of pancreatic cells surrounding a metastasis. Sections of pancreas from six normal subjects showed only slight tissue acid phosphatase activity. The possible sources of the increased serum acid phosphatase are discussed, and it is suggested that the pancreas could be the source of such increased activity in our second case.