OR3A4 promotes the proliferation, migration, invasion, and tumorigenesis of gastric cancer cells by activating genes involved in cell migration and invasion (MACC1, GNB2L1, DLX4, PDLIM2, and NTN4), metastasis (DLX4), growth (PIWIL1, MACC1, GAS6, HOXB7, GNB2L1, and DLC-1), cellular adhesion (PDLIM2, NTN4, and CTNND1) and cell cycle progression (CORO1C). The gene discussed is PIWIL1; the disease is gastric cancer.