HAVCR2 (TIM-3) as a favorable prognostic immune marker in seminoma: Integrative checkpoint screening and tissue validation.

BACKGROUND

Immune checkpoint inhibitors targeting the PD-1/PD-L1 axis have demonstrated limited efficacy in testicular germ cell tumors (TGCTs), highlighting the need to identify alternative immune biomarkers. We evaluated the prognostic significance of HAVCR2 (TIM-3) in seminoma using an integrative approach combining transcriptomic analysis, penalized regression screen, and independent tissue-level validation.

METHODS

Elastic net-penalized Cox regression was applied to a four-gene immune checkpoint panel (HAVCR2, PDCD1, LAG3, TIGIT) in the TCGA seminoma cohort. Survival analyses were performed using progression-free interval (PFI). Findings were validated in an independent tissue microarray (TMA) cohort using immunohistochemistry. A pooled analysis integrating transcriptomic and protein-level data was conducted using a standardized biomarker approach.

RESULTS

HAVCR2 retained a relatively larger non-zero coefficient after penalization, whereas PDCD1, LAG3, and TIGIT were attenuated. In the TCGA cohort, higher HAVCR2 expression showed a trend toward improved PFI (log-rank p = 0.120). In the TMA cohort, high TIM-3 expression was associated with favorable relapse-free survival (log-rank p = 0.053), with all relapse events in the low-expression group. In the pooled cohort, HAVCR2/TIM-3 expression was associated with improved event-free survival (log-rank p = 0.019; HR = 0.201, p = 0.035); permutation-corrected p = 0.164, and findings are exploratory.

CONCLUSION

HAVCR2/TIM-3 expression demonstrates a consistent association with favorable clinical outcomes in seminoma across transcriptomic and protein-level analyses, with a lower risk of progression (HR = 0.201) in the pooled cohort. These exploratory findings support a potential prognostic role of TIM-3 reflecting an immune-active rather than exhausted microenvironment in seminoma, warranting prospective validation.