6th ESACP Congress, Heidelberg, April 7-11, 1999

A056
DIFFERENT PATTERN OF CHROMOSOMAL ABERRATIONS IN THE PROGRESSION OF BREAST CANCER
Friedrich K, Scheithauer J, Haroske G, Dimmer V, Meyer W, Theissig F, Kunze KD

Institute of Pathology Hospital of University of Technology, Dresden, Germany

The aim of the study was to detect chromosomal imbalances in different stages of tumor progression. The numerical chromosomal aberrations were examined by CGH in sixty breast cancers. The DNA-ploidy was estimated by image cytometry. The number of chromosomal aberrations increase from the peridiploid via the peritetraploid to the aneuploid tumors. The aneuploid breast cancers exhibit the highest number of chromosomal losses, including also regions harboring tumor suppressor genes like p53, DCC and DCP. The peritetraploid group was characterized by a similar number of chromosomal gains and losses of tumor suppressor gene loci . The gains in the peritetraploid tumors include also regions of oncogenes like c-myc and c-erb-B2. An increase of tumor size was associated with gain on 8q and losses on 12q. Tumors with lymphnode metastases exhibit also gains on 8q, here including the region of c-myc and additionally losses on 18q. The gene locus of c-erbB-oncogene and the distal region of 8q were gained in breast can cers with a Bloom-Richardson grade 3. In conclusion, the progression of breast cancer is accompanied by an increase of chromosomal aberrations with gains of regions harboring oncogenes and losses including tumor suppressor genes, too. The gain of 8q, including the c-myc oncogene, seems to be a common features during the tumor progression of mammary gland. Other chromosomal aberrations are associated with different features of a malignant disease, reflecting the multiple genomic influences on the tumor phenotype.