52_01

The estrogen receptor is present in 70% of DCIS but the rate of expression is higher in low-grade lesions (90%) than in high-grade lesions (25%). This association with histologic grade is reversed for the rate of overexpression of HER2/neu proto-oncogene and the p53 tumor suppression gene. Approximately 50% of all DCIS lesions have overexpression of HER2/neu, and in 25% the p53 tumor suppressor gene is also detected. Both of these molecular markers are noted in 20% of low-grade lesions but are present in approximately two thirds of high-grade lesions.