The AUCs of serum LDHC for BC (36), HCC (37), and LUAD (63) reached 0.9587, 0.8382, and 0.8121, respectively, whereas those of serum-sourced LDHC for BC, HCC, and LUAD reached 0.9464, 0.9451, and 0.8925, respectively, higher than the corresponding values for serum LDHC. These data indicate that LDHC is a promising novel non-invasive marker for tumor diagnosis. Here, LDHC is linked to neoplasm.