Genetic alterations, including changes in the expression of spastic paraplegia 20 (SPG20) and serine/threonine protein kinase 31 (STK31), may play an important role in the carcinogenesis of colorectal cancer (CRC). Identification of such changes is suitable for the recognition of tumors at an early stage, which would significantly improve patient survival. While recent studies have identified that SPG20 and STK31 expression levels increase in CRC tissues, their use as a biomarker is yet to be investigated. Our aim was to determine whether circulating SPG20 and STK31 mRNAlevels could help distinguish between patients with CRC and healthy individuals. Additionally, we aimed to analyze the correlation between SPG20 and STK31 expression patterns and the tumor stage in patients with CRC.