Low protein expressions of ALDH1A1, ALDH1A2, ALDH1A3, ALDH1B1, ALDH1L1, ALDH3A2, ALDH3B1, ALDH3B2, ALDH4A1, ALDH5A1, ALDH6A1, ALDH7A1, ALDH8A1, ALDH9A1, and ALDH16A1 were found in HCC tissues, while their medium and high protein expressions were observed in normal liver tissues. Here, ALDH6A1 is linked to hepatocellular carcinoma.