Western blot analysis of c-Mpl and GPIIb/IIIa expression in the platelets from ET patients (P1 to P17), a CML patient (CML), and normal controls (C1 to C4). The platelet lysates (15 μg each lane) were separated by SDS-PAGE and probed with either anti-c-Mpl or anti-GPIIb/IIIa antiserum.