[Demonstration of two regions involved in chromosome 1p deletion in breast tumors]

Alteration of chromosome 1 is the most consistent cytogenetic abnormality found in human breast carcinoma. Cytogenetic studies have shown independent 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 carried out deletion analysis of the 1p region by using restriction fragment length polymorphism markers mapping to the long (six markers) and short arm (22 markers). Thirty-five of the 74 (47%) human breast tumors tested showed somatic loss of heterozygosity at one or more loci on 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 the short arm of the chromosome 1.