The expression of ALDH family in all cancers of TCGA. (A) The expression level of patients of ALDH family in 33 types of cancer in TCGA. (B) The correlations among the expressions of the ALDH family. (C) The relative expression levels of ALDH1A1, ALDH1B1, ALDH2, ALDH9H1, ALDH3B1, and ALDH18A1 in the TCGA database compared with normal tissues. (The number of normal tissue samples less than 3 was hidden). *P < 0.05, ***P < 0.001.