Figure 5

CD271 ^high brain metastases lack expression of MITF. (A) Co-immunohistochemistry of a solitary BM of patient 1 (two different tumor areas) as well as multiple BM of patient T1 for CD271 (membrane, red) and MITF (nuclear, brown). (B) Upper and center panels: Staining of patient 1 BM for CD271 and Ki67. Lower panel, quantification of Ki67⁺, CD271⁺ and double positive cells of BM (n = 5) and EM (n = 6). (C) MITF expression levels (log2) of CD271^high and CD271^low BM of two independent studies (GSE50493, GSE44660) are shown. (D,E) GSEA of BM subsets analyzed in (C) and T20/02 cells with over expression of CD271 (T20/02^CD271/NGFR) for enrichment of MITF-target genes as provided by TCGA⁴³, compared to untransfected cells (Mock) is shown. In addition, GSEA revealed enrichment of melanoma aggressiveness-associated genes in A375 cells (CD271/NGFR vs. GFP) and BM. In (B) and (C) p-values were calculated by Wilcoxon rank-sum test.