Relationship between molecular subtypes and differentiation degree of breast cancer with metastasis at Dr. M. Djamil General Hospital, Padang

Abstract

Background: Breast cancer remains the most prevalent malignancy among women worldwide and represents a major cause of cancer-related mortality. Metastasis is the leading determinant of poor prognosis and mortality in breast cancer patients. Molecular subtyping, including Luminal A, Luminal B, HER2-positive, and Triple Negative Breast Cancer (TNBC), has been recognized as an important prognostic and predictive factor influencing the metastatic potential. In addition, histological differentiation grade reflects tumor aggressiveness and correlates with disease progression. However, the association between molecular subtype, histological differentiation, and metastasis remains controversial across studies and populations. Objective: To investigate the relationship between molecular subtypes and differentiation degree of breast cancer with the occurrence of metastasis among patients at Dr. M. Djamil General Hospital, Padang, Indonesia. Methods: A cross-sectional study was conducted on female breast cancer patients diagnosed between January 2020 and December 2024 who underwent immunohistochemistry evaluation for ER, PR, HER2, and Ki-67. Molecular subtypes were classified into Luminal A, Luminal B, HER2-type, and TNBC, while histological grading was assessed based on the Nottingham Grading System. Data were obtained from medical records and analyzed using Chi-square test, with a significance level set at p