SMPD3 and head and neck squamous cell carcinoma: In agreement, our analysis of unpaired normal and tumor data from TCGA shows that hypermethylation of SMPD3 occurs in bladder urothelial carcinoma, breast invasive carcinoma, colon adenocarcinoma, head and neck squamous cell carcinoma, liver hepatocellular carcinoma, kidney renal papillary cell carcinoma, lung adenocarcinoma, lung squamous cell carcinoma, thyroid carcinoma, and uterine endometrial carcinoma, but not prostate cancer (Supplementary Figure 2).