CYTOGENETIC COMPARISON OF PRIMARY TUMORS AND LYMPH-NODE METASTASES INBREAST-CANCER PATIENTS

Chromosome banding analysis of primary tumors and axillary lymph node metastases from IO breast cancer patients revealed abnormal karyotypes in all samples with cytogenetic similarities between the primary tumo r and the metastasis in all informative pairs. Although karyotypically unrelated clones were also bound in the lymph node samples, they were less numerous than in the primary tumors, indicating that there was m ore genetic heterogeneity among the neoplastic cells in the primary th an in the secondary tumors. On the other hand, some of the clones had become more complex in the metastases as a result of clonal evolution, and by and large these metastatic breast cancer cases had more karyot ypic anomalies than do unselected primary breast carcinomas. Among the aberrations occurring more frequently, and that consequently may pred ispose to disease spread, were losses of chromosomes 17 and 22 and hom ogeneously staining regions, a cytogenetic sign of gene amplification. (C) 1998 Wiley-Liss, Inc.