Notably, while the expression of EPO is not recognized as a good marker for diagnosis, the erythroid progenitors are more proliferative and are hypersensitive to EPO in polycythemia vera patients [55,56], which is similar to the process that EMPs are more responsive to EPO, are more proliferative, and are able to generate more mature erythrocytes in B10.S mice by HgCl2 exposure. This evidence concerns the gene EPO and acquired polycythemia vera.