Establishment of a Human Small Cell Lung Carcinoma Cell Line Carrying Amplification of c‐myc Gene and Chromosomal Translocation of t(3p;6p) and t(12q;17p)

A transplantable tumor and an in vitro culture cell line (GK‐T3) were established from metastatic liver tissue of human small cell lung carcinoma (SCLC). Southern blot analysis revealed about 30‐fold amplification of c‐myc gene in the tumor cells in liver, xenografts, and in vitro cell line. The degree of c‐myc amplification was essentially conserved through serial passages in nude mice and cultivation in vitro. The level of c‐myc mRNA was significantly increased in these cells. Cytogenetically, numerical and complex structural abnormalities were observed in GK‐T3 cells, including t(3p;6p), t(12q;17p), two homogeneously staining regions (hsrs) and several double minutes (dmins). These results suggest that activation of c‐myc gene and alteration of gene(s) round these chromosomal breakpoints may play a role in tumorigenesis of GK‐T3 SCLC.