COMPARATIVE GENOMIC HYBRIDIZATION OF FORMALIN-FIXED, PARAFFIN-EMBEDDED BREAST-TUMORS REVEALS DIFFERENT PATTERNS OF CHROMOSOMAL GAINS AND LOSSES IN FIBROADENOMAS AND DIPLOID AND ANEUPLOID CARCINOMAS

Comparative genomic hybridization serves as a screening test for regio ns of copy number changes in tumor genomes. We have applied the techni que to map DNA gains and losses in 33 cases of formalin-fixed, paraffi n-embedded primary breast tumors (13 fibroadenomas and 10 diploid and 10 aneuploid carcinomas). No genomic imbalances were found in fibroade nomas. Recurrent findings in adenocarcinomas include copy number incre ases for chromosomes 1q (14 of 20 samples), 8q (10 of 20), 17q (5 of 2 0), 6p (3 of 20), 13q (3 of 20), and 16p (3 of 20), and copy number de creases for chromosomes 22 (7 of 20), 17p (6 of 20), and 20 (3 of 20). Regional high level copy number increases were observed on chromosome bands 1q32, 8p11, 8q24, 10p, 11q13, 12p, 12q15, 17q11-12, and 17q22-2 4. The majority of the samples were studied for gene amplification of c-myc, c-erbB2, cycD1, and int-2 by means of Southern blot analysis. T he comparison with DNA ploidy measurements revealed a different distri bution and a significantly higher number of chromosomal