LAUSR

OBJECTIVE Gastrointestinal tumors are malignant tumors with high morbidity. Mitochondrial serine hydroxymethyltransferase 2 (SHMT2) is a key enzyme in the synthesis of serine and glycine, which has prognostic and therapeutic value for many malignant tumors. However, the role of SHMT2 in gastric cancer (GC), esophageal cancer (ESCC), and colorectal cancer (CC) has not been clarified. PATIENTS AND METHODS The expression of SHMT2 was detected in GC, ESCC, and CC by immunohistochemistry and reverse real time transcription-polymerase chain reaction. The relationships between SHMT2 expression and clinicopathologic characteristics, recurrence-free survival (RFS), and disease-specific survival (DSS) were analyzed by the survival analysis and correlation analysis. RESULTS The positive expression rate of SHMT2 in GC, ESCC, and CC was 74.1%, 69.2%, and 71.7%, respectively. Patients with high expression of SHMT2 had a worse prognosis. In GC, high SHMT2 expression had positive correlation with lymph node metastasis (p=0.005) and histological grade (p=0.002). In ESCC, high SHMT2 expression had positive correlation with pT classification (p=0.033) and pM classification (p=0.029). In CC, high SHMT2 expression had positive correlation with tumor size (p=0.004), lymph node metastasis (p=0.035), TNM stage (p=0.007), and histological grade (p=0.020). Notably, SHMT2 expression was an independent prognostic factor for RFS and DSS in GC, ESCC, and CC (p<0.05). CONCLUSIONS SHMT2 is upregulated in GC, ESCC, and CC. The high expression of SHMT2 is correlated with gastrointestinal tumors progression, and poor prognosis, which is a potential new target for the diagnosis and treatment of gastrointestinal tumors.