The presence of additional pathogenic non-driver mutations was investigated, and an additional mutation was detected in 6 of the 7 cases, being DNMT3A (ET and PMF), NFAIP3 (ET), TP53 (post-PV MF), SF3B1 (pre-PMF), and CUX1 (PMF). Here, CUX1 is linked to essential thrombocythemia.