eng Oriental Scientific Publishing Company Biomedical and Pharmacology Journal 0974-6242 2025-09-30 18 3 2290 2297 10.13005/bpj/3255 67398 article Ngakan Ketut Wira Suastika 1 Ketut Suega 1 Department of Internal Medicine Faculty of Medicine, Udayana University, Denpasar, Indonesia Non-Hodgkin lymphoma (NHL) comprises a diverse array of lymphoid malignancies with different clinical presentations and prognostic outcomes. Ki-67, a nuclear protein, is a potential biomarker for assessing disease aggressiveness and predicting therapeutic responses in NHL. This retrospective cohort study aimed to evaluate the association between Ki-67 expression, aggressiveness, and therapeutic response in 87 patients with NHL who received first-line chemotherapy. Ki-67 expression was assessed using immunohistochemistry, and the therapeutic response was evaluated based on the International Working Group Consensus Response Evaluation Criteria in Lymphoma (RECIL 2017). Significant differences in Ki-67 expression levels were found between aggressive and indolent NHL (p < 0.001) and between the stable-progressive disease and partial-complete response groups (p = 0.006). A Ki-67 expression cut-off of >55% distinguished aggressive from indolent NHL, with an area under the curve (AUC) of 0.938 (p < 0.001). In aggressive NHL, a Ki-67 expression cut-off of >75% predicted stable-progressive disease (AUC = 0.719, p = 0.005) with a relative risk (RR) of 2.07 (p = 0.042). In indolent NHL, a cut-off of >35% was not statistically significant for predicting therapeutic response. These findings suggest an association between Ki-67 expression, aggressiveness, and therapeutic response in patients with NHL. However, further studies with larger cohorts are required to validate Ki-67 as a reliable and independent predictor in clinical practice. https://biomedpharmajournal.org/vol18no3/ki-67-expression-as-a-biomarker-for-aggressiveness-and-therapeutic-response-in-non-hodgkins-lymphoma/ Aggressiveness Biomarker Ki-67 Non-Hodgkin's lymphoma Therapeutic response