A region of deletion on chromosome 22q13 is common to human breast and colorectal cancers.

Chromosomal allelic losses have varying frequency in breast cancer, with key regions including chromosomes 1, 3p, 7q, 9p, 16q, 17, and 22q. Recently, we have been able to map a new target region of allelic loss on chromosome 22q involved in colorectal cancer. The aim of the current investigation was to determine whether this target region may also be involved in human breast carcinogenesis. Thirty-six pairs of matched normal and tumor specimens from breast cancer patients, as well as eight breast cancer-derived cell lines, were genotyped using 17 microsatellite markers spanning chromosome 22q. Allelic deletion was found in 19 of 36 tumors (53%), and the pattern observed in those cases with partial losses was consistent with a region flanked by D22S1171 and D22S928. This interval overlaps that identified in colorectal cancer and comprises nearly 1.1 Mb. This study provides evidence of a common region of deletion on chromosome 22q13 involved in both breast and colorectal cancers and underscores the existence of putative tumor suppressor gene(s) at this location.