GENETIC-HETEROGENEITY OF PRIMARY AND METASTATIC BREAST-CARCINOMA DEFINED BY FLUORESCENCE IN-SITU HYBRIDIZATION

Breast carcinoma is frequently, associated with nonrandom chromosomal aberrations, but their identification by standard cytogenetics (SC) is often limited by technical difficulties. Fluorescence in situ hybridi zation (FISH) studies of interphase nuclei can circumvent some of thes e difficulties and has the potential to identify non-random molecular cytogenetic events occurring in breast cancer FISH was Performed on tu mor nuclei isolated from 15 formalin-fixed, paraffin-embedded archival breast carcinomas using a panel of chromosome-specific alpha-satellit e probes for enumerating chromosomes in interphase nuclei, Freshly iso lated cells from these same cases had previously been studied by stand ard cytogenetics and FISH, In addition to archival primary carcinoma, archival metastases and normal tissue were also studied by FISH. Genet ic numerical alterations were identified by standard cytogenetics or F ISH in 14 of 15 carcinomas. Numeric alterations initially identified b y standard cytogenetics were confirmed by FISH in 9 of 10 cases, Resul ts of FISH performed on nuclei isolated from paraffin-embedded materia l were in agreement with FISH Performed on freshly isolated cells. Clo nal numeric alterations were observed in the archival primary tumor as well as in metastases. Archival normal tissue was consistently disomi c.