Elevated TROP-2 in Papillary RCC Supports ADC Therapeutic Potential

Overview

This study identifies significantly elevated TROP-2 expression in papillary renal cell carcinoma (pRCC) compared to other RCC subtypes and benign renal tumors. The findings suggest that TROP-2 is a promising target for antibody-drug conjugate (ADC) therapy, exemplified by sacituzumab govitecan (SG), which demonstrated preclinical antitumor activity in RCC cell lines.

Background

Renal cell carcinoma (RCC) comprises clear cell RCC (ccRCC) and non-clear cell RCC (nccRCC), with papillary RCC (pRCC) being the most common nccRCC subtype. Despite advances in ccRCC treatment, therapeutic options for pRCC remain limited. Antibody-drug conjugates (ADCs) targeting tumor-associated antigens like TROP-2 have shown efficacy in other epithelial cancers. TROP-2 is a transmembrane glycoprotein overexpressed in various tumors and associated with aggressive disease.

Data Highlights

Key Findings

• TROP-2 mRNA and protein expression are significantly higher in pRCC tumor tissues compared to ccRCC, chRCC, benign renal tumors, and controls.
• Immunohistochemistry revealed strong membranous TROP-2 staining in pRCC specimens, with H-scores indicating moderate to strong expression.
• Serum TROP-2 levels measured by ELISA correlate with tumor tissue expression, suggesting potential as a non-invasive biomarker.
• Sacituzumab govitecan (SG), a TROP-2-targeting ADC, demonstrated preclinical antitumor activity in RCC cell lines, including those derived from pRCC.
• The study cohort included 88 RCC patients and 17 controls, with standardized tissue and serum collection protocols ensuring robust data.

Clinical Implications

The elevated expression of TROP-2 in pRCC supports its role as a viable therapeutic target for ADCs such as sacituzumab govitecan. Measurement of serum TROP-2 may serve as a surrogate biomarker to identify suitable patients and monitor treatment response. These findings justify further clinical evaluation of TROP-2-directed ADC therapies in pRCC, addressing the unmet need for effective treatments in this RCC subtype.

Conclusion

This study establishes TROP-2 as a highly expressed antigen in papillary RCC, highlighting its promise as a target for antibody-drug conjugate therapy. The preclinical efficacy of sacituzumab govitecan in RCC models warrants clinical investigation to improve outcomes in pRCC patients.

References

1. ARON-1 Study Group 2023 -- Real-world outcomes in metastatic papillary RCC
2. Bardia et al. 2021 -- Sacituzumab govitecan in triple-negative breast cancer
3. Tagawa et al. 2022 -- TROPHY-U-01 trial in metastatic urothelial carcinoma
4. WHO Classification 2022 -- Tumors of the urinary system and male genital organs