PATTERNS OF CHROMOSOMAL IMBALANCES IN ADENOCARCINOMA AND SQUAMOUS-CELL CARCINOMA OF THE LUNG

Comparative genomic hybridization was used to screen 25 adenocarcinoma s and 25 squamous cell carcinomas of the lung for chromosomal imbalanc es. DNA copy number decreases common to both entities were observed on chromosomes 1p, 3p, 4q, 5q, 6q, 8p, 9p, 13q, 18q, and 21q. Similarly, DNA gains were observed for chromosomes 5p, 8q, 11q13, 16p, 17q, and 19q. Adenocarcinomas showed more frequently DNA overrepresentations of chromosome Iq and DNA losses on chromosomes 3q, 9q, 10p, and 19, wher eas squamous cell carcinomas were characterized by increased overrepre sentations of chromosome 3q and 12p as well as deletions of 2q. For th e first time, we used a histogram representation and statistical analy sis to evaluate the differences between both tumor groups. In particul ar, the overrepresentation of the chromosomal band 1q23 and the deleti on at 9q22 were significantly associated with adenoid differentiation, whereas the DNA loss of chromosomal band 2q36-37 and the overrepresen tations at 3q21-22 and 3q24-qter were statistically significant marker s for the squamous cell type. The study strengthens the notion that di fferent tumor subgroups of the respiratory tract are characterized by distinct patterns of chromosomal alterations.