A positive significant correlation between NRP-1 RNA and LDH (r=0.912, p=0.011) was detected in relapsed AML patients with no other significant correlation between NRP-1 RNA and any other parameters: age, TLC, Hb, platelet count, PB blast %, BM blast %, CD33, CD13, CD14, CD117, myeloperoxidase, CD2, CD5, CD7, CD34, HLA-DR, and CD10. This evidence concerns the gene NRP1 and acute myeloid leukemia.