Although mechanistic explanations for why elevated platelets and MKs inhibit MM progression are still lacking, we speculate that the following possibilities, alone or in combination, might account for the inhibition: First, PF4 is a major chemokine secreted from megakaryocyte which inhibits the progression of MM43,44, suggesting that MKs may inhibit the progression of MM by secreting PF4. The gene discussed is PF4; the disease is Miyoshi myopathy.