CALR and acquired polycythemia vera: With the identification of the JAK2V617F-mutation in 2005 [63–66], reports on the potential of IFN-alpha2 to induce major molecular remissions in JAK2V617-positive patients [19, 26–50] and later on after the discovery of the CALR-mutations in 2013 [67–69], a reduction in the CALR-mutational load as well [39, 43], the interest in treatment of PV and related neoplasms with IFN-alpha2 has been revived as reviewed in several papers during the last 5–10 years [19–26, 55, 56].