Objective To investigate the expressions of stern cell markers CD133,nestin and CD44 in malignant melanoma and their significance.Methods Tissue samples were obtained from 30 patients with malignant melanoma and 30 patients with intradermal nevus.The expressions of three markers were immunohistochemically detected in the samples.Results In malignant melanoma specimens,the expression rate of CD133,nestin and CD44 was 53.33%(16/30),80.00%(24/30)and 20.00%(6/30),respectively,significantly difierent from that in intradermal nevus specimens [23.33%(7/30),53.33%(1 6/30)and 0,respectively,all P＜0.05].The percentage of cells positive for CD133,nestin and CD44 was 2.98%±5.62%,34.92%±34.89%and 1.28%±3.26%,respectively,in malignant melanoma specimens.0.10%±0.21%,7.26%±13.13%and 0,respectively,in intradermal nevus specimens;there was a significant difierence between the two groups of specimens(all P＜0.05).In malignant melanoma and intradermal nevus,the expression intensity of CD133.nestin and CD44 showed no significant correlation with patients'sex.age or disease course(all P＞0.05).ConclusionsCD133,nestin and CD44 are highly expressed in malignant melanoma,but weakly expressed or absent in intradermal nevus,suggesting that tumor stem cells might exist in malignant melanoma tissue.