CANT1 as a novel prognostic biomarker in triple‑negative breast cancer

Triple‑negative breast cancer (TNBC) is one of the most aggressive breast cancer subtypes, with limited targeted treatment options and poor clinical outcomes. Calcium‑activated nucleotidase 1 (CANT1), a calcium dependent enzyme involved in nucleotide metabolism and glycoprotein processing, has attracted limited attention in oncology and its clinical relevance in breast cancer remains unknown. The present study hypothesized that CANT1 expression may carry prognostic information in TNBC and evaluated its association with clinicopathologicalal features and survival. In the present retrospective study, 59 non‑metastatic patients with TNBC who underwent curative surgery were included. CANT1 expression was assessed using immunohistochemistry and semiquantitatively scored using an H‑score ranging from 1‑300. Patients were categorized into three groups according to H‑score (H1, 1‑100; H2, 101‑200; H3, 201‑300). Associations between CANT1 expression and clinicopathologicalal variables were analyzed using the χ2 or Fisher's exact test and survival outcomes were evaluated using the Kaplan‑Meier method, log‑rank test and Cox proportional hazards model. CANT1 expression was successfully evaluated in all tumors: 15 patients (25.4%) were classified as H1, 29 (49.2%) as H2 and 15 (25.4%) as H3. The median overall survival (OS) for the entire cohort was 40.2 months, with a median follow‑up of 48.4 months. Median OS by expression group was 29.2 months in H1, 36.7 months in H2 and not reached in H3 (log‑rank P=0.033). In the multivariable analysis, high CANT1 expression (H3 vs. H1) remained independently associated with improved OS (P=0.048; hazard ratio=0.149; 95% CI, 0.031‑0.715). To the best of our knowledge, the present study is the first to investigate CANT1 expression in TNBC. High CANT1 expression was significantly assocaited with improved OS, suggesting that CANT1 may serve as a novel prognostic biomarker in TNBC. Further multicenter and mechanistic studies are warranted to clarify its biological role and prognostic utility.