Background: Dickkopf-1 (DKK-1), an inhibitor of the Wnt signaling pathway, is known as an inhibitor of melanocyte proliferation. In recent studies, the expression of DKK-1 gene is reduced in melanoma and they lose their preventive role during development or progression of melanoma. There are no available data regarding the changes in DKK-1 gene expression in acral lentiginous melanoma (ALM), which is common in Asians. Objective: To analyze changes in DKK-1 expression in the development or progression of ALM in Koreans. Methods: Immunohistochemical staining using DKK-1 antibody of 13 invasive ALM, six ALM in situ, nine acral nevi, and four benign non-related palmoplantar specimens as controls were evaluated by the semi-quantitative grading scale, which is divided into three distinctive grades according to the degree of cytoplasmic staining of DKK-1. Results: Among the invasive ALM specimens, seven of 13 (53.8%) were graded as strongly positive (2＋), and only one case (7.7%) was negative. In cases of ALM in situ, two specimens (33.3%) stained positive (1＋) and the remaining four specimens (66.6%) were not stained. All specimens from both acral nevus and benign palmoplantar lesions, which were used as the control group, were also negative. Conclusion: In contrast with recent reports, DKK-1 expression showed a positive correlation with ALM progression or invasiveness. The role of DKK-1 as a potential predictor of ALM progression warrants further study. (Korean J Dermatol 2018;56(4):259∼264)