CLONAL CHROMOSOME-ABNORMALITIES IN HUMAN BREAST CARCINOMAS .1. 28 CASES WITH PRIMARY DISEASE

Cytogenetic analysis was performed on a selected series of short-term cultures of primary breast carcinomas from 28 patients. All patients h ad histopathologically confirmed malignancies, with the majority (25/2 8 cases) demonstrating infiltrating ductal carcinoma. All 28 cases evi denced clonal chromosome abnormalities, with 10/28 displaying only num eric aberrations, whereas 18/28 displayed clonal structural alteration s. In near-diploid tumors the most common numeric changes were - 17 an d - 19. However, trisomy 7 was the only numeric change in two near-dip loid tumors. Structural chromosome alterations were primarily isochrom osomes, apparent terminal deletions, and unbalanced non-reciprocal tra nslocations. Chromosomes 1 (10/18-56%) and 6 (8/18-44%) were most freq uently altered in this series. Breakpoints of clonal structural abnorm alities were shown to cluster to several chromosome segments, includin g 1 p22-q11, 3p11, 6p11-13, 7p11-q11, 8p11-q11, and 19q13. Analysis of the gain or loss of specific chromosome segments revealed that the mo st consistent tendency was over-representation of 1q, 3q, and 6p. (C) 1993 Wiley-Liss, Inc.