Assessment of USP17 and TPT1 Expression in Primary and Matched Metastatic Tissue of Patients with High-Grade Serous Ovarian Carcinoma and the Relationship to Distant Metastasis

Objectives: Deubiquitinating enzymes have been increasingly implicated in tumor progression and metastasis. Ubiquitin-specific protease 17 (USP17) and translationally controlled tumor protein 1 (TPT1) are associated with cell proliferation, migration, and cancer progression; however, their differential expression in matched primary and metastatic tissues of high-grade serous ovarian carcinoma (HGSC) has not been well defined. This study aimed to compare USP17 and TPT1 expression between matched primary and metastatic HGSC tissues and to explore their association with metastatic disease. Methods: This retrospective study included 33 patients diagnosed with HGSC. Immunohistochemical analysis of USP17 and TPT1 expression was performed using tissue microarrays (TMA) constructed from matched primary ovarian tumor tissues and corresponding metastatic tissues. USP17 expression was evaluated using a semi-quantitative composite immunohistochemical scoring system, while TPT1 expression was assessed using a semi-quantitative immunoreactivity index. Paired statistical analyses were applied to compare expression patterns between primary and metastatic tissues. Results: Primary and metastatic USP17 expression levels showed a positive correlation (Spearman’s rho = 0.349, p = 0.047) whereas paired comparison showed no significant difference between the two sites (p = 0.438). In contrast, TPT1 expression showed no statistically significant correlation (Spearman’s rho = 0.285, p = 0.107) or paired comparison showed no difference (p = 0.107) between matched primary and metastatic tissues. USP17 and TPT1 expression levels were significantly positively correlated in both primary (Spearman’s rho = 0.406, p = 0.019) and matched metastatic tissues (Spearman’s rho = 0.351, p = 0.045). Neither USP17 nor TPT1 expression showed a significant association with International Federation of Gynecology and Obstetrics (FIGO) stage, lymph node involvement, or receipt of neoadjuvant chemotherapy (NACT). Conclusions: These findings indicate a positive correlation between USP17 expression in paired primary and metastatic HGSC tissues without significant changes in overall expression levels, though causality cannot be inferred. Conversely, TPT1 expression showed no significant correlation or site-specific variation between matched tumor tissues. Further prospective and functional studies are required to validate these findings and clarify their biological significance.