Background: Vimentin3 (Vim3) was recently described as a tumor marker for the direct differentiation between benign and malignant kidney tumors. Our group recently reported correlation between Vim3 overexpression and increasing migration of PCa cell lines.Objectives: Comparing Vim3 serum levels among different PCa grades.Design Setting and Participants: serum samples obtained. from PCa patients (n=314) between 2017 and 2020 were classified according to the grade group system and analysed by ELISA, and Western Blot to measure Vim3 levels. Additionally, Paraffin embedded human PCa samples from radical prostatectomy specimens were stained immunohistochemically for Vim3 (n=10).Outcome Measurements and Statistical Analysis: Vim3 levels in serum samples show a correlation with increasing aggressiveness of PCas. ANOVA analysis was used.Results and limitations: the Vim3 protein level increased significantly (p<0.001) with increasing biological aggressiveness of human PCa specimens from prostate biopsies and/or radical prostatectomy specimens (Gleason ≥8). A "grey-zone" value for Vim3 was determined (300-350 ng/ml). Furthermore, Vim3 levels in the Gleason >7 group (3+4) (4+3), metastasis, castration resistant and castration responder was analysed. Vim3 levels significantly decrease in the group of ADT responders. Limitations include the retrospective and single centre design. Conclusion:Vim3 could be a new surrogate biomarker for the classification and graduation of PCa, especially for PCa with increasing metastatic potential. Additionally, we hypothesised that Vim3 determination can be usable for ADT respond control.