CHARACTERIZATION OF 9Q, 15Q WHOLE-ARM TRANSLOCATION DERIVATIVES IN NONSMALL CELL LUNG CARCINOMAS BY FLUORESCENCE IN-SITU HYBRIDIZATION

We report derivative chromosomes, originally interpreted as 9q;15q who le-arm translocations, in tumor cells from two patients with non-small cell lung cancer (NSCLC). One of the tumors was diagnosed as an adeno carcinoma and the other as an adenosquamous carcinoma. In each case, t here was no normal chromosome 9. Because of the pericentromeric locati on of the breakpoints, classical cytogenetic banding techniques did no t permit determination of the centromeric origin of these derivative c hromosomes. Fluorescence in situ hybridization (FISH) with satellite ( alpha, beta, classical), ribosomal DNA, alpha-interferon (alpha-IFN), and whole chromosome painting probes indicated that the 9;15 rearrange ment is dicentric in both tumors. In one of these cases, the derivativ e chromosome is interpreted as a dic(9;15) (p11;p11.2); the other case has a more complicated rearrangement involving reorientation of peric entromeric sequences. A 9q;15q whole-arm derivative chromosome was rep orted previously in another lung adenocarcinoma, suggesting that this abnormality may represent a recurrent change in lung carcinomas, parti cularly those displaying adenomatous features.