TP53 ALTERATIONS IN ATYPICAL DUCTAL HYPERPLASIA AND DUCTAL CARCINOMA IN-SITU OF THE BREAST

Abnormalities in the TP53 tumour suppressor gene in 75 atypical ductal hyperplasias and 62 ductal-carcinomas in situ (DCIS) of the breast we re studied using immunohistochemistry and mutation analysis, Accumulat ion of p53 protein was detected in 10 out of 62 (16%) DCIS, whereas no cases of positive staining was observed in the atypical lesions. TP53 mutations were identified in four out of 30 (13%) DCIS by constant de naturant gel electrophoresis (CDGE). Two of these cases were positive and two negative for p53 protein. A total of 12 out of 62 DCIS (19%) c arried TP53 mutation and/or p53 protein overexpression. The present re sults suggest that TP53 alterations may be important in the developmen t of a subset of DCIS.