MPL/JAK2 mRNA and protein expression in platelets of MPN patients. Platelets were collected from patients diagnosed with PMF or ET, or from healthy donors (Controls C1 to C4). MPL/JAK2 protein expression was evaluated by immunoblotting for ET patients (A) and PMF patients (B) and was compared with normal controls (C). MPL/JAK2 protein expression, normalized with that of GpIb, was quantified using imageJ. (D) Quantification of JAK2 protein expression in platelets of MPN patients according to the MPL/JAK2 mutational status. (E) Quantification of MPL protein expression in platelets of MPN patients according to their MPL and JAK2 mutational status. (F) JAK2 protein expression and (G) JAK2 mRNA expression were determined for PMF an ET samples. (H) MPL protein expression and (I) MPL mRNA expression were determined for PMF and ET samples. Error bars indicate mean ± standard error of the mean. *P < .05; **P < .01.