<![CDATA[Breast cancer is a malignancy with high molecular complexity. The expression of the BRCA1 protein, as a tumor suppressor gene, and the HER2 receptor status, as a prognostic and therapeutic target marker, are two important factors in determining cancer subtypes. This study aims to analyze the correlation between BRCA1 Expression and HER2 Status in breast cancer patients in West Nusa Tenggara (NTB), Indonesia. This study used an observational analytic design with a cross-sectional approach, utilizing secondary data from the medical records of breast cancer patients in hospitals in NTB. The study sample consisted of 50 cases that met the inclusion and exclusion criteria. BRCA1 Expression and HER2 Status were determined using Immunohistochemistry (IHC) examination. Data were analyzed using the Lambda correlation test to measure the strength and direction of the relationship between variables. Among the 50 breast cancer patients, 50% showed positive BRCA1 expression and 50% showed positive HER2 status. The Lambda test yielded an Approximate Significance value of 0.125 (p > 0.05), with a Lambda Symmetric coefficient of 0.000. These findings indicate no statistically significant association between BRCA1 expression and HER2 status among breast cancer patients in West Nusa Tenggara (NTB). No statistically significant association was found between BRCA1 expression and HER2 status in breast cancer patients in NTB. However, these findings should be interpreted considering the cross-sectional design, relatively small sample size, and the distinction between BRCA1 protein expression assessed by immunohistochemistry and BRCA1 gene mutation status. This local dataset may provide preliminary information for further genetic and molecular research on the pathogenesis of breast cancer in this region.]]>
