The decrease in the expression of T-cell markers, such as CD2, CD3, CD5 and CD7, in MF patients is based on the idea that as the disease progresses, a predominant abnormal phenotype is identified.6, 13 Reduction of CD2, CD3 and/or CD5in at least 50% of lymphoid cells is an importantly sensitive criterion for identification of T-cell lymphomas.20 This evidence concerns the gene CD5 and mycosis fungoides.