Conclusions
We found that the PD-L1 expression in the bone marrow megakaryocytes of JAK2-mutated PMF patients was higher than the control group. This may confirm the hypothesis that the oncogenic JAK2 mutation enhances the PD-L1 promoter activity and its expression in JAK2 positive patients. We hypothesize that patients with high PD-L1 expression may benefit from checkpoint inhibitors, in combination with JAK2 inhibitors, in the upfront setting of therapy.