LDHC and hepatocellular carcinoma: This study also found the expression of LDHC in serum-derived exosome of LUAD patients for the first time, and the two existing forms of LDHC (serum and exosomes) have high application value in the diagnosis, efficacy evaluation, and recurrence monitoring of LUAD, which is consistent with LDHC expression in BC and HCC verified by previous studies (13, 14).