Analysis of chromosomal aberrations in breast cancer by comparative genomic hybridization (CGH). Correlation with histoprognostic variables and c-erbB-2 immunoexpression

The establishment of additional powerful prognostic markers in breast cance r patients is of unquestionable importance given that breast cancer is char acterized by morphologic, biologic and genetic heterogeneity. In the pre se nt study we analyzed 8 primary invasive breast carcinomas by comparative ge nomic hybridization (CGH) in order to find and map the DNA copy number chan ges occuring in these tumors. Furthermore, in order to evaluate the potenti al prognostic significance, we compared these genetic changes with other hi sto- and immunopathologic prognostic variables, such as tumor type, tumor g rade, lymph node status, estrogen receptors content and c-erbB-2 oncoprotei n expression. All the studied cases showed a wide variety of gains and loss es of chromosomal regions or arms distributed among 16 chromosomes with an average number of 6.12 aberrations per case. Although several genetic chang es appeared to be common, none was unique or consistent in all the studied cases. The most consistent regions of gain were on Iq, 20q and 8q while the most common regions of loss on 3p and 6q. Accumulation of chromosomal chan ges were more frequently found in high grade ductal breast carcinomas with overexpression of c-erbB-2 oncoprotein in both lymph node-negative and lymp h node-positive patients, whose tumors were positive for estrogen receptors . If any of these genetic changes identified by CGH in breast cancer patien ts carry prognostic information, regardless of stage or other factors predi ctive of biologic behavior, further investigation is needed.