Although no direct link between the allele frequencies of mutated JAK2 alleles in the BMB was found, differences in the composition of the BM TME between MPN samples with driver mutations in JAK2 or CALR/MPL as well as TN cases were detected, which were associated with a lower expression of IFN- γ signaling components in JAK2 wild type MPN. The gene discussed is MPL; the disease is myeloproliferative disorder.