In triple-negative breast cancer (TNBC) diagnosed at stage I, the tumour’s immune signals and its proliferative activity appear to push prognosis in contrary directions. A retrospective study suggests that integrating both could sharpen risk stratification in a group that still lacks reliable tools.
What was already known
About one third of patients with TNBC are diagnosed at stage I. Despite being early tumours, the lack of biomarkers that separate those at low risk from those who are not remains an unmet need. That is the space where gene signatures and immune markers aim to prove useful.
What this work adds
This is a retrospective study that retrieved tissue samples and clinicopathological data from consecutive patients with stage I TNBC. A total of 253 patients were analysed; most tumours were ductal (88.9%) and high-grade (73.1%), and 65.2% of patients received adjuvant chemotherapy. TNBC-DX-type gene signatures, stromal tumour-infiltrating lymphocytes (sTILs) and an immune score (CIG) were assessed.
Main results
With 18 recurrence events observed, 3-year recurrence-free survival (RFS) in the overall cohort was 95.0% (95% CI: 92.1-98.1) and 3-year overall survival was 97.9% (95% CI: 95.9-100.0). No significant differences in RFS were seen by TNBC-DX category (117 patients) or sTILs category (123 patients). However, the 29 patients in the highest CIG quartile showed a 3-year RFS of 100% (95% CI: 100-100), and patients with high sTILs (>20%) had a 3-year RFS of 97.0% (95% CI: 90-100). By contrast, a high TNBC-DX proliferation score was numerically associated with poorer outcomes, with a 3-year RFS of 83% (95% CI: 68-100).
What it means
The authors conclude that, in this retrospective study, immune and proliferative features show opposing prognostic trends and that integrating them may improve risk stratification, warranting further investigation. For a patient, this means there is still no single validated biomarker to safely decide who can receive less treatment in early TNBC: these are research hypotheses, not a clinical decision guide. The cohort size and its retrospective nature require confirmation in prospective studies before any practical application.
Reference: Tarantino P, Li T, Paré Brunet L, Sanfeliu E, Koca B, Guo R, et al. Association of immune and proliferation gene signatures and stromal tumor-infiltrating lymphocytes with clinical outcomes in patients with stage I triple-negative breast cancer. European Journal of Cancer, 2026. DOI/link
