ALLELIC IMBALANCE IN THE REGION OF THE BRCA1 GENE IN DUCTAL CARCINOMAIN-SITU OF THE BREAST

Thirty-four cases of ductal carcinoma in situ (DCIS) of the breast, wi th or without associated benign or invasive disease, were anlaysed for allelic imbalance (AI) in the region of the BRCA1 gene. AI on 17q12-2 3 in DCIS was demonstrated in 74% of cases, and in the majority of cas es the region of AI included the BRCA1 gene. However, two cases showed AI distal to BRCA1, supporting the presence of a second tumour-suppre ssor gene on 17q.