Histological grade, p53, HER2 and hormone receptor status of synchronous bilateral breast carcinoma

Background and Objectives: Histological grade and tumor biology remain important predictors of the clinical behavior of breast carcinomas. We analyzed the clinicopathological characteristics and tumor biology with regard to histological grade (HG), p53, HER2 and hormone receptor status to address this question. Patients and Methods: A consecutive series of 74 female synchronous bilateral breast carcinoma patients treated at the National Cancer Center Hospital were the primary source of these retrospective data. Clinicopathological background factors, histological grade and immunohistochemical staining for p53, HER2 and hormone receptor status, were analyzed. Results: Of 148 synchronous bilateral tumors, 102 were invasive ductal carcinoma (IDC). The others included 24 pure or predominant ductal carcinoma in situ (DCIS), 5 spindle cell carcinomas, 16 invasive lobular carcinomas and 1 squamous cell carcinoma. 128 cases (128/148: 89%) were HG 1 (72/148: 49%) or HG 2 (56/148: 38%). The positivity rates for p53, HER2, estrogen receptor (ER) and progesterone receptor (PR) were 9% (14/148), 18% (26/148), 64% (95/148) and 64% (95/148), respectively. Conclusion: Our findings indicate that synchronous bilateral breast carcinomas showed a higher frequency of invasive lobular carcinoma, lower HG and higher rate of hormone receptor positivity than unilateral breast carcinomas.