Karyotypic evolution in breast carcinomas with i(1)(q10) and der(1;16)(q10;p10) as the primary chromosome abnormality

The pattern of clonal karyotypic evolution in br east carcinomas carrying a n i(1q) or a der(1;16)(q10;p10) as the primary chromosome abnormality was a ssessed in a series of 42 tumors, including 8 described here for the first time, with either or both (3 tumors) of them defining cytogenetic features. Evidence of clonal evolution was seen in somewhat more than half of all ca ses in both subgroups. The secondarily acquired aberrations appeared to be nonrandom in distribution. This was as especially so for structural rearran gements of 11q leading to loss of material from this am, which were clearly more common in both subgroups than in karyotypically abnormal breast carci nomas in general. Other deviations from random were less certain but seemed to include the frequent occurrence of +20 in tumors with i(1q) and +7 in t umors with der(1;16)(q10;p10). That differences were observed between i(1q) carcinomas and der(1;16)(q10;p10) carcinomas with regard to their patterns of clonal evolution hints that the pathogenetic effect of the primary chan ge in these two situations may be more than the mere gain of an extra copy of 1q. (C) Elsevier Science Inc., 1999. All rights reserved..