The diagnostic value of lysosomal enzyme patterns in bronchial aspirates of patients with suspected bronchial carcinoma.

The measurement of the activity of acid hydrolases and of alkaline phosphatase in bronchial aspirates obtained through bronchoscopic procedures from a series of 300 patients forms the basis for a screening program to diagnose bronchial malignant neoplasms more effectively. We define such a screening test as one permitting rapid measurements indicative of pathologic abnormalities and producing a preliminary diagnosis which, if in error, yields preferably a false-positive result. Using this approach, we demonstrated that an elevation of the activity of alkaline phosphatase or cathepsin D predicts a 50 percent likelihood of cancer, but elevation of both the concentrations of alkaline phosphatase and cathepsin D has an additive prediction of 71 percent. Data obtained in this study showed that the presence of a pulmonary tumor can cause increased levels of alkaline phosphatase or cathepsin D (or both) in bronchial aspirates before the presently accepted methods yield a diagnostic result. Furthermore, those patients with an elevated activity of alkaline phosphatase or cathepsin D (or both) but with no histologically demonstrable pulmonary carcinoma can be reexamined intermittently.