In this study, we investigated the effects of GPR34 knockdown on proliferation of LS174T colon cancer cells, as well as PI3K subunits/AKT and ERK expression, with the aim of evaluating whether the expression of GPR34 may regulate the growth and proliferation of colon cancer cells, and exploring the details of the underlying mechanisms. The gene discussed is PIK3CD; the disease is malignant colon neoplasm.