CYTOGENETIC FINDINGS IN INVASIVE BREAST CARCINOMAS WITH PROGNOSTICALLY FAVORABLE HISTOLOGY - A LESS COMPLEX KARYOTYPIC PATTERN

Seventeen invasive primary breast carcinomas of histological types usu ally considered to be prognostically favourable (2 medullary, 3 papill ary, 3 tubular, and 9 mucinous carcinomas) were analysed as part of an ongoing study of the cytogenetics of breast cancer. Thirteen of the t umours (7 mucinous, 2 medullary, 2 papillary, and 2 tubular carcinomas ) showed clonal chromosome aberrations. Trisomy 7 and i(1 q) were pres ent as sole and recurrent aberrations in the mucinous tumours. The 2 t ubular carcinomas and I papillary carcinoma had simple numerical chang es only, whereas the second papillary tumour had a balanced translocat ion as the sole anomaly. Both medullary carcinomas had chromosome numb ers in the triploid range, with clones displaying structural and numer ical changes. Our data, especially when collated with information on p reviously published cases of mucinous, papillary, tubular, and medulla ry breast carcinomas, show that the former 3 histological types, in ke eping with their recognised prognostic advantage, appear to exhibit re latively simple karyotypic changes, i.e., numerical aberrations, balan ced translocations, and near-diploid chromosome numbers, Medullary car cinomas on the other hand, appear to have more complex karyotypes, sim ilar to those described for the more common ductal and lobular subtype s of breast carcinoma. Int. J. Cancer (Pred. Oncol.) 79:361-364, 1998. (C) 1998 Wiley-Liss, Inc.