In one of the largest ET studies comparing JAK2V617F mutated (n=414) to unmutated cases (n=362), there was no significant difference in survival, leukemic or MF transformation rates.62 Other studies confirmed the lack of correlation related to JAK2 mutational status and disease transformation.32, 63, 64 Interestingly, in a large multicenter study by Barbui et al.34 the presence of JAK2V617F mutation significantly decreased the rate of MF progression (HR 0.37; 95% CI, 0.17–0.79, P=0.15) among ET patients but did not influence LT or overall survival. The gene discussed is JAK2; the disease is essential thrombocythemia.