SHMT2 and neoplasm: In addition, SHMT2 (r = 0.326, p < 0.001) and MTHFD2 (r = 0.241, p < 0.001) were positively correlated with tumor size (Fig. 2c), whereas most of the other genes in the SGP group exhibited weak (r < 0.2) or no significant correlation (p > 0.05).