[Resected lung cancer with production of CA19-9]

We report 2 cases of resected CA19-9 producing adenocarcinoma of the lung. Immunohistochemical studies of the specimens in 2 cases showed positive staining for CA19-9 in most of tumor cells. The serum CA19-9 levels decreased after operations and effective chemotherapy in these cases. But the serum CA19-9 levels increased with regrowth of tumors or with no therapeutic gain by chemotherapy. The serum CA19-9 level was useful to evaluate the therapeutic effect of surgery and chemotherapy, and may be effective in detecting the recurrence of lung cancer.