Biomarkers of response to antibody-drug conjugates (TROP2 and nectin-4) and the immune microenvironment (NKG7, PD-L1, and B7-H3) in penile squamous cell carcinoma

Objectives We aimed to assess the expression of biomarkers of response to antibody-drug conjugates (TROP2 and nectin-4) and immune microenvironment (NKG7, PD-L1, and B7-H3) in penile squamous cell carcinoma (pSCC). Methods Our archive was queried for patients who had a penectomy for pSCC between 2000 and 2022. Primary tumors were immunostained for B7-H3 and NKG7, while metastatic specimens were immunostained for TROP2 and nectin-4. Expression of PD-L1, TROP2, and nectin-4 in primary tumors was previously characterized. H-scores (0-300) were used to quantify expression. Associations between biomarkers, tumor-infiltrating lymphocytes (TILs), and clinicopathologic and outcome parameters were evaluated. Results For both TROP2 and nectin-4, H-scores within the lymph node metastases were higher compared to those within the primary tumors (mean, 264.5 vs 244.8, P = .0003; mean, 170.6 vs 146.7, P = .05, respectively; 33 paired specimens). For B7-H3 (n = 107), 32.7% of the primary tumors had an H-score of more than 0. In 34.8% of the cases, NKG7 expression was observed in 25% to 50% of the TILs. A significant association was noted between TIL density, B7-H3, NKG7, and PD-L1 expression. Conclusions Therapeutic strategies targeting TROP2 and nectin-4 hold promise for patients with advanced pSCC. The potential of PD-L1, B7-H3, and NKG7 for predicting response to immunomodulatory treatment warrants further research. The Author(s) 2025.