Breast cancer classification according to immunohistochemistry markers: subtypes and association with recurrence in an oncology hospital database, Baghdad.

Abstract

BACKGROUND: Breast cancer is comprised of a series of complex and heterogeneous subtypes with difference in clinicalbehavior and outcomes. The immunohistochemistory defined subtypes have a predictive significance and prognostic value inbreast cancer. There are limited data regarding immunohistochemistory defined subtypes among Iraqi breast cancer patients. Theobjective of this study was to study the prevalence of immunohistochemistory defined subtypes and to identify their associationswith the risk of recurrence.PATIENTS AND METHODS: A study included 150 patients with breast cancer attending Baghdad oncology teaching hospitalbetween June 2019 and December 2019 (50 cases with negative recurrence history and 100 recurrence cases) for whom data includingage, stage, grade, histopathological type, date of recurrence for recurrence cases and date of last follow-up for cases withnegative recurrence history were collected. The breast cancer subtypes defined using immunohistochemical measures of hormonereceptors and human epidermal growth factor receptor 2 and classified into four major subtypes: luminal A, luminal B, HER2-positive, and triple negative. the association between these subtypes and the recurrent history was evaluated by Chi-squared test.RESULTS: The mean (±SD) age was 48.4 (±10.8) years. The immunohistochemistory defined subtypes of cancer was shown:luminal A in 79(52.7%)patients, 24(16%)patients had luminal B, 15(10%)patients had HER2 positive and 32(21.3%)patients hadtriple negative breast cancer. there were a significant association between immunohistochemistory defined subtypes and recurrenthistory (p=0.012).CONCLUSION: Tumor profiling using molecular subtypes is a promising agent to identify a cases at high risk of recurrence.