During this time, unpublished studies in our laboratory indicated that peripheral blood blasts from some patients with AML lacked expression of PSGL-1 as analyzed by flow cytometry, but Western blots of lysates of these blasts probed with either the anti-sLeX mAb HECA-452 or with E-selectin–Ig chimera (E–Ig) showed staining of a band migrating at ∼250 kDa. The gene discussed is SELPLG; the disease is acute myeloid leukemia.