SOMATIC DNA ALTERATIONS IN BREAST CARCINOMAS OF DIFFERENT LYMPH-NODE STATUS BY DNA FINGERPRINT ANALYSES

The purpose of this study tvas to screen for somatic changes in invasi ve breast tumors by multilocus DNA fingerprints comparing normal (bloo d) and malignant tissue samples from 34 patients. The comparison of ly mph node-positive and node-negative breast carcinomas was of primary i nterest. After restriction enzyme digestion with HinfI and HaeIII, alt ered banding patterns were detected by using the oligonucleotide probe (GTG)(5) in 7 of 34 (20.5%) and in 3 of 34 (8.8%) tumors after hybrid ization with (GACA)(4). The overall frequency of changes thus amounted to 29.4%. Because long (GACA)(n) repeat motifs, generating predominan t DNA fingerprint bands, are localized on the short arms of the human acrocentric chromosomes, sequences that are important in breast carcin ogenesis may be present in these regions. The overall methylation stat us of the DNA does not appear to be responsible for DNA fingerprint di fferences, as can be demonstrated with the restriction endonuclease Ha eIII. DNA fingerprint differences did not correlate with tumor grade, stage, and hormone receptor status. Tumors with lymph-node metastases expressed DNA fingerprint differences more frequently. (C) Elsevier Sc ience Inc., 1998.