PPT1 and lip and oral cavity carcinoma: The genes PPT1 (palmitoyl-protein thioesterase 1), LILRA4 (leukocyte immunoglobulin-like receptor A4), and HCK (hemopoietic cell kinase) were correlated with a lower risk of oral cancer, while TNFRSF13C (tumor necrosis factor receptor superfamily member 13c) was linked to a higher risk.