Clinicopathologic Characteristics of Molecular Subtypes of Breast Cancer and Their Predictive Implications in Breast Cancer Treatment

INTRODUCTION: As far as recent breast cancer molecular subtype classification is concerned, much work has dealt with clinical outcomes for triple negative (TN) and HER2 patients. Less is known about the course of patients in the remaining subtypes. OBJECTIVES: : The aim of our investigation was to correlate immunohistochemical subtypes of breast cancer with clinical and pathological characteristics. MATERIALS AND METHODS: Since 2003 till 2011 year 475 patients operated for invasive breast tumours were included in our database. In total, luminal A subtype was observed in 31. 37% of cases, luminal B in 46. 95%, HER2 in 6.53%, but TN in14.53%. Patients were regularly followed up until December 2011. RESULTS: Our study demonstrates that patients with HER-2 and triple negative breast cancer subtype had more worse course and prognosis compared to luminal A and luminal B subtype. Patients with HER2 cancer subtype had the greatest median tumour size, whereas the rate of sentinel lymph node positivity was significantly higher in the triple negative compared to HER2 subtype. In addition, the positive correlation between luminal A and TN, but no luminal B and HER2 tumour size and positive sentinel lymph node was observed. In addition, a positive correlation between tumour size and disease stage was observed only for TN subtype, where a correlation between tumour size and Grade was observed only for luminal A subtype. CONCLUSION: Our study demonstrates that patients with HER-2 and triple negative breast cancer subtype had more inferior prognostic implications compared to luminal A and luminal B subtypes. The size of luminal A and TN tumour correlated with SN positiviry, whereas TN size correlated with disease stage. KEYWORDS: breast cancer, molecular subtypes.