2 DISTINCT REGIONS INVOLVED IN 1P DELETION IN HUMAN PRIMARY BREAST-CANCER

Alteration of chromosome 1 is the most consistent cytogenetic abnormal ity found in human breast carcinoma. Cytogenetic studies have shown in dependent alterations on the two arms of chromosome 1; increased copy number of the long arm and loss of the short arm of chromosome 1. We c arried out deletion analysis of the 1p region by using restriction fra gment length polymorphism markers mapping to the long (six markers) an d short arm (22 markers). Thirty-five of the 74 (47%) human breast tum ors tested showed somatic loss of heterozygosity at one or more loci o n the short arm. Two commonly deleted regions, 1p13-p21 and 1p32-pter, were identified. Our findings suggest that two tumor suppressor genes involved in the development of human breast carcinoma may occur on th e short arm of the chromosome 1.