PDCD1 and melanoma: Besides, serum S‐100B and lactate dehydrogenase (LDH) concentrations are widely used as prognostic biomarkers in advanced melanoma.18 During dosing with various drugs, serum S‐100B and LDH levels in CAH (+)‐treated mice were insignificantly different from those of healthy mice, but were statistically lower as compared to other treatments including PD‐1, DTIC, 5‐ALA (+), and control (+) mice (Figure 7D,E).