LOSS OF HETEROZYGOSITY IN SPORADIC HUMAN BREAST-CARCINOMA - A COMMON REGION BETWEEN 11Q22 AND 11Q23.3

The development of sporadic human breast cancer is associated with the accumulation of genetic alterations on several chromosomes. In the ca se of chromosome 11, loss of heterozygosity (LOH) at loci on the short arm has been well documented and suggests the presence of a suppresso r gene(s) at 11p15.5. However, the evidence for similar events on the long arm is less compelling. Here, we determined the prevalence of LOH for chromosome 11q in 44 malignant and 3 benign cases of unselected s poradic breast tumor samples. We found that alteration of chromosome 1 1q is common in the pathogenesis of breast cancer as 19 of 44 (43%) ma lignant tumor specimens exhibited LOH. Eleven (58%) of these genetic a lterations were specific to the long arm of the chromosome. The smalle st region of shared LOH places the target between 11q22 and 11q23.3, t he same general region frequently altered in cancers of the ovary, col on, skin, and uterine cervix, perhaps indicating the location of a tum or suppressor gene or genes of importance in each of these different t umor types.