SATB1 and CD30 expression in cutaneous CD30⁺LPDs. (A) Paraffin-embedded tissues from LyP, PCALCL, and MF-LCT patients were analyzed with immunohistochemistry. The large, atypical tumor cells showed bright diffuse nuclear staining of SATB1, and they coincided with CD30 staining (original magnification ×400, scale bar = 20 µm). (B) Immunofluoresence with double staining demonstrated specific SATB1 expression (red) in CD30⁺ cells (green) in LyP, whereas the surrounding reactive small T cells were negative for SATB1 or CD30. DAPI (blue) was used for visualize cell nuclei (scale bar = 25 µm). (C) SATB1 protein expression was detected in all 3 PCALCL cell lines with Western blot. Jurkat and Hut78 cell lines, derived from T lymphoblasts and Sézary cells, respectively, served as controls for high and low SATB1 expression in CD30⁺ T cells. (D) SATB1 expression levels relative to CD30 in CD30⁺LPD clinical samples. PCALCL⁺, PCALCLs positive for SATB1; PCALCL^–, PCALCLs negative for SATB1; Pt, Patient no. *P < .05. Biological replicates for each cell were repeated 3 times.