Molecular cytogenetic analysis of non-small cell lung carcinoma by spectral karyotyping and comparative genomic hybridization

The overall pattern of chromosomal changes detected by spectral karyotype (SKY) analysis of two cell lines of each major histological subtype of NSCLC, namely squamous cell carcinoma (SQCC) and adenocarcinoma (ADC), indicated a greater degree of chromosomal rearrangement, than was present or predicted by either comparative genomic hybridization (CGH) or G-banding analysis alone. To investigate these observations, CGH was used to screen DNA derived from 8 primary tumors and 15 cell lines. The results indicated that the most frequently gained chromosome arms were 5p (70%), 8q (65%), 15q (52%), 20q (48%), 1q (43%), 19q (39%), 3q (35%), and 11q (35%). Chromosomal losses were less frequently observed, and included 18q (39%), 9 (35%), 6q (30%), 13q (21%), 5q12–q32 (17%), and 19p (17%). Amplifications were found on 2p23–p24, 3q24–q27, 5p, 6cen–p21.1, 6q26, 7p21, 7q31, 8q, 11q13–qter, 20q12–q13.2. Comparison between CGH findings of the two major histological subtypes showed that gains at 1q22–q32.2, 15q, 20q, and losses at 6q, 13q, and 18q was common in ADCs, whereas SQCCs exhibited gains/amplifications at 3q. Distal 8q was gained by CGH in 65% of tumors of both subtypes. Low level MYCC amplification was confirmed by direct fluorescence in situ hybridization (FISH) analysis. The pattern of overall chromosomal changes detected using combinations of molecular cytogenetic analytical methods suggests that it will be easier to detect recurrent subtype-dependent aberrations in NSCLC.