CYP26A1 and neoplasm: Consistent with our results, ALDH6A1, FBP1, HAO2 and PSAT1 were found to be significantly downregulated in tumor samples compared with normal samples in both Oncomine and TIMER database (supplementary figure 3A,B); TYMP, HK3, and P4HA3 were found to be significantly overexpressed in tumor samples in both Oncomine and TIMER database, while IL4I1 and CYP26A1 were found over-expressed only in TIMER database (supplementary figure 4A,B).