The Roles of Vitamin D Receptor (VDR) and CD8+ T‐Lymphocytes in Acral and Mucosal Melanoma Invasion Depth.

Background: Acral and mucosal melanomas, the most common sun‐shielded site melanoma subtypes in Asia and Indonesia, often yield poor prognoses. The invasion depth reflects their progressivity, and the pathogenesis is influenced by vitamin D receptor (VDR) status and CD8+ T‐Lymphocyte amount. This study aims to determine the association between the invasion depth of acral and mucosal melanomas with their VDR and CD8+ immunoexpression. Methods: A cross‐sectional observational study was conducted on 60 formalin‐fixed paraffin‐embedded (FPPE) samples, with equal representation in acral and mucosal melanoma groups from 2017 to 2021. The samples were assessed for the invasion depth and immunoexpression of VDR and CD8+. A chi‐square test with an alternative Exact–Fisher analysis was used to determine the association between the variables in both subtype groups. Results: An association between VDR and CD8+ immunoexpression and invasion depth in acral melanoma (p value = 0.0001 and 0.009, respectively) was observed, while only VDR immunoexpression was associated with the invasion depth in mucosal melanoma (p‐value =0.004). Interestingly, no association was found between CD8+ immunoexpression and the invasion depth in mucosal melanoma (p = 0.640). Conclusion: The role of VDR and CD8+ T‐lymphocytes are inversely associated with melanoma depth in acral melanoma, while only VDR is associated with melanoma depth in mucosal melanoma. [ABSTRACT FROM AUTHOR]