Objectives: Transforming growth factor-beta (TGFβ1) is involved in tumorigenesis and metastasis. It provides this effect both by disrupting the thiol-disulfide balance and through the cancer-upregulated gene (CUG2) and transforming growth factor beta-induced (TGFBI) genes in the signaling pathway. In this study, the roles of TGFβ1 and related genes, as well as thiol-disulfide balance, in the formation of prostate cancer and metastasis were investigated. Methods: Tissue samples were taken from 33 benign prostatic hyperplasia (BPH) and 35 prostate cancer (PC) patients to determine the Gleason score and metastasis. TGFβ1, CUG2, and TGFBI gene expression levels were measured by RT-PCR. Serum prostate specific antigen (PSA) levels were measured in patients, and PSA density (PSAD) was calculated. Total thiol and native thiol measurements in serum were performed spectrophotometrically, and disulfide was calculated. Results: In patients with prostate cancer and metastases, PSA and PSAD levels were high, while total thiol and native thiol were significantly lower (p<0.05). TGFβ1, CUG2 and TGFBI gene expression levels were higher in patients with prostate cancer and metastases and were negatively correlated with total thiol and native thiol (p<0.001). Conclusions: As a result of our study, we determined that the increase in TGFβ1, CUG 2 and TGFBI in prostate cancer plays an important role in cancer formation and metastasis by disrupting the thiol-disulfide balance.