Our findings are in accordance with the results of a recent study that demonstrated that PAR1 expression is downregulated in primary AML cells.46 Furthermore, Par1 homozygous null mutant mice develop leukemia with a shorter latency than control animals in secondary transplantation experiments.46PAR2 is involved in migration and/or proliferation of many cancer cells, including breast,47 pancreatic48 or colon49 cancer and seems to have a role in tumor angiogenesis through vascular endothelial growth factor production in cancer cells.50 This evidence concerns the gene F2R and leukemia.