Routine histologic examination of a right axillary lymph node showed paracortical infiltration of conspicuous atypical small-to-medium sized lymphocytes, positive for CD2, CD3, CD4 and TCRβF1, with partial loss of CD5 and CD7 (Figure 1D), consistent with lymph node involvement of MF (Dutch grade N3). The gene discussed is CD5; the disease is mycosis fungoides.