The result shows that mRNA expressions of ALDH1B1, ALDH1L1, ALDH2, ALDH4A1, ALDH5A1, ALDH6A1, ALDH7A1, ALDH8A1, and ALDH9A1 were significantly lower in HCC tissues (Fig. 3). Here, ALDH7A1 is linked to hepatocellular carcinoma.