Tissue factor pathway inhibitor 2 (TFPI2) is a potential serum biomarker for clear cell renal carcinoma

Renal and ovarian clear cell carcinoma (CCC) are both characterized by a clear cytoplasm and exhibit similar genomic alterations and clinical characteristics. We hypothesized that both CCCs may share clinical biomarker. Tissue factor pathway inhibitor 2 (TFPI2), a serine protease inhibitor, has emerged as a promising serum biomarker for ovarian CCC, and we evaluated the efficacy of TFPI2 as a biomarker for renal cell carcinoma (RCC). Serum samples were collected from patients with RCC and healthy volunteers, and TFPI2 levels were measured. Expression of TFPI2 in each cell type was evaluated using single-cell RNA sequencing. Survival analyses according to TFPI2 expression levels were performed based on publicly available databases. Serum TFPI2 was significantly elevated in patients with RCC compared to healthy volunteers, particularly those with clear cell histology. Metastatic RCC tumors exhibited higher TFPI2 than localized RCCs. Moreover, higher TFPI2 correlated with higher Fuhrman grades in clear cell RCC. Publicly available databases showed an association between TFPI2 expression and overall survival, particularly in clear cell RCC. Single-cell RNA sequencing confirmed TFPI2 expression in clear cell RCC and normal kidney tubular epithelial cells. TFPI2 has emerged as a potential serum biomarker for RCC, offering avenues for improved detection and prognostication.