Material and Method: A retrospective cross-sectional study was performed, in which immunohistochemistry (IHC) was used to evaluate the expression of TOX, FOXP3, CD4 and GATA3 in formalin-fixed paraffin-embedded (FFPE) sections of skin lesions from 30 cases with BID and 30 patients with early-stage MF. This evidence concerns the gene CD4 and mycosis fungoides.