ALLELIC LOSS ON CHROMOSOME-17 IN DUCTAL CARCINOMA IN-SITU OF THE BREAST

Multiple tumor suppressor genes are implicated in the oncogenesis and progression of invasive carcinoma of the breast. To investigate the ch ronology of genetic changes we studied loss of heterozvgosity on chrom osome 17 in ductal carcinoma in situ, a preinvasive breast cancer. A m icro-dissection technique was used to separate tumor from normal strom al cells prior to DNA extraction and loss of heterozygosity was assaye d mainly using simple sequence repeat polymorphism markers and the pol ymerase chain reaction. Loss of heterozygosity on 17p was observed in 8 of 28 tumors (29%) when compared with normal control DNA, whereas no loss was seen on 17q, suggesting that at least one locus on 17p is in volved early in the development of breast cancer.