The Association between Molecular Subtypes of Breast Cancer with Histological Grade and Lymph Node Metastases in Indonesian Woman

Objective: Breast carcinoma is a heterogeneous disease which is rich in diversity. Molecular subtypes of breastcancer, histological grade and lymph node metastases are strong prognostic and predictive factors. In Indonesia,only a limited number of studies have investigated the correlation between molecular subtypes with histologicalgrade and lymph node metastases. Methods: We analyzed 247 invasive breast carcinoma cases from the AnatomicPathology Installation of Dr. Sardjito General Hospital Yogyakarta between 2012-2015. The slides were stained forestrogen receptors (ER), progesterone receptors (PR), HER2, Ki-67 and CK5/6 for classification into breast cancersubtypes (BCS). Histological grade using the Nottingham system and lymph node status were obtained from anatomicpathology records. The association between histological grade and lymph node status with BCS was examined withChi-square tests. Results: The immunohistochemical features of 247 cases of women with invasive breast carcinomawere examined. There were 102 (41.3%) patients with Luminal A, 34 (13.8%) patients with Luminal B, 48 (19.4%)patients with HER2-positive, and 63 (25.5%) patients with triple negative breast cancer (TNBC). There were 148(59.9%) patients with negative lymph node status and 99 (40.1%) with positive status. Among 63 TNBC cases, 37(58.7%) patients were positive for CK5/6 staining (basal-like). Statistically, there were significant differences betweenhistological grade and subtypes (p=0.013). However, no significant differences were found for lymph node metastases(p=0.540). Conclusion: Among subtypes, Luminal A has the highest frequency, followed by TNBC, HER2-positiveand Luminal B. Histological grade was associated with molecular subtypes of breast carcinoma in Yogyakarta. GradeI was associated with Luminal A, while Grade III was associated with Luminal B, HER2 and TNBC subtypes.