A new human lung poorly differentiated adenocarcinoma cell line producing carcinoembryonic antigen (CEA) and CA19-9, designated GLL-1, was established from a serial xenograft established in our laboratory. In this paper, we investigated the characteristics of GLL-1 cells. The cell line grew in a monolayer and had a polygonal epithelioid appearance in phase-contrast microscopy. The doubling time of GLL-1 cells during exponential growth was approximately 28 h in RPMI-1640 with 10% fetal calf serum. Positive reactions for CEA and for CA19-9 were seen within the cytoplasm of GLL-1 cells by immunohistochemical staining. In log phase, the fractions for G0/G1, S and G2/M were 76.2%, 20.0% and 3.8%, respectively. Chromosome analysis revealed that GLL-1 cells contained the modal number of 72 chromosomes (range 66-97). GLL-1 cells exhibited numerous numerical and structural abnormalities. The Do value for radiation sensitivity, calculated by taking the reciprocals of the slope of the radiation dose response curve, was 109 cGy. The extrapolation number (n) for the radiation response curve was 1.57. Tumor take was observed in nude mice inoculated subcutaneously in the back with 2 x 10(6) GLL-1 cells. The histopathological features of the tumor induced by inoculation of GLL-1 cells were also the same as the original lung cancer.