Primary lung cancer producing alpha-fetoprotein: a case report.

A case of primary lung cancer that produced both alpha-fetoprotein (AFP) and carcinoembryonic antigen (CEA) is presented. Alphafetoprotein in the supernatant of tissue extract from the primary lesion amounted to more than 40 microgram/ml, and its exact origin from tumor tissues was confirmed by the immunofluorescent study. We suppose that since the lung is one of the foregut derivatives it is not unlikely for lung cancer cells to produce AFP as well as CEA.