GP9 and Down syndrome: In addition, CMK cells, which were derived from a Down’s syndrome patient suffering from AMKL, expressed high levels of CD41a (72.1%), and Dami cells, which were derived from an AMKL patient, expressed high levels of CD41a (64.2%), CD42a (89.8%), and CD42b (66.1%); these cells represent more differentiated megakaryocytic cell lines compared with HEL and Meg-01 cells (Fig. S1) [13], [14].