PDCD1 and melanoma: Seban et al. [144] in a retrospective study on 55 melanoma patients undergoing 18F-FDG PET/CT before anti-PD1, reported that low tumor burden (TMTV = total metabolic tumor volume; <25 cm3) correlates with survival and objective response, while hematopoietic tissue metabolism (BLR > 0.79; SLR > 0.77) inversely correlates with survival.