Racial differences in ductal carcinomas of the breast and DCIS

A74 Ductal carcinomas of the breast (BCa) are reported to be more aggressive lesions in African-Americans (AAs) than in Caucasian Americans (CAs); therefore, we studied the pathophysiological and molecular differences in BCas between AAs and CAs in order to characterize factors leading to differences in aggressiveness. Background: BCas with higher grades (poorer differentiation) and higher stages (e.g., tumors with metastases) have in general a poorer outcome than BCas with lower stages and grades. Also, BCas have been reported to occur at younger ages in AAs than in CAs. Methods: We randomly selected cases from archival cases from the University of Alabama within the following constraints: 100 females, pre-menopausal with BCa, grade matched as to their BCas with 100 post-menopausal cases with BCas. Paraffin blocks were collected and brightfield immunohistochemistry was performed on these case and the results analyzed based on race. Results: Within our selection criteria, our results indicate that in younger (pre-menopausal) AAs, higher grade lesions are more common (85%) than in CAs (39%). Similarly, in the case of BCa in post-menopausal women, AAs still have a greater proportion of higher grade lesions (64.5%) than CAs (39%). We found that estrogen receptors (ER) and progesterone receptors (PR) were significantly (p ≤ 0.005) more positive in CAs than in AAs and that Bcl-2, and membrane expression of p185 erbB-2 was higher significantly (p ≤ 0.03) in BCas from CAs than in BCas from AAs. We found no racial differences in p53, p27, Ki67, cytoplasmic or membrane expression of EGFr and cytoplasmic expression of p185 erbB-2 or size of the tumors or lymph node involvement. Expression of Bcl-2 and p53 in BCas have been reported to be inversely related. We found this to be the case for all patients (AA + CA, p = 0.002) and for CAs (p = 0.022). Because the number of African-Americans were low, n = 47, their association did not reach statistical significance (p = 0.071) even though the pattern of association in AAs was very similar to that in CAs. In conclusion, we identified several factors that would predict a poorer outcome of AAs with BCas including high grade lesions, lower expression of ER and PR and lower expression of Bcl-2. The higher expression of p185 erbB-2 on cellular membranes in CAs would not support BCas in AAs being more aggressive than BCas in CAs. Evaluation of DCIS is underway and will be reported. Sponsored in part by the Susan G. Komen Breast Cancer Foundation Grant to William E. Grizzle (BCTR0600484) and Upender Manne (POP0601383) and the Early Detection Research Network Grant to William E. Grizzle (5U24CA086359).