Skin mucin deposition is mainly due to hyaluronic acid, acidic mucopolysaccharide, and a significant increase in mucin, which is deposited diffusely or restrictively in the skin. Clinical use of Alisin blue staining to further identify various types of blood cells to improve the diagnosis of acute promyelocytic leukemia is of great significance. Alisin blue staining procedure: 1. 5 parts of 200g/L potassium ferricyanide plus 1 part of concentrated hydrochloric acid, freshly prepared, filtered and ready for use. 2.Fix the bone marrow slice with methanol for 10min. 3.Add the above-prepared staining solution and stain for 30min, rinse with tap water. If the room temperature is too low, the staining time can be extended. 4.Re-stain with 5g/L saxifrage aqueous solution for 1min. wash, air dry and microscopic examination.