Fig. 4

Expression of β-catenin in melanoma brain metastases. (A) Digital images (40X magnification) corresponding to representative tissue sections obtained from craniotomy specimens that were immunohistochemically stained with an antibody against β-catenin (ImmPACT VIP, purple; methyl green, cyan). Examples of melanoma cells expressing β-catenin in the nucleus (3+, upper left, red arrows) and, cytoplasm (3+, upper left, yellow arrows; 2+, center left, yellow arrows). Tumor-infiltrating lymphocytes (TILs, upper left and center left, blue arrows) do not express β-catenin whereas neurons (upper right, green arrows) have strong β-catenin expression. (B) Expression of β-catenin in different cell compartments (melanoma cells, TILs, glia cells, and adjacent normal brain tissue). Wilcoxon test was performed to compare β-catenin expression between melanoma cells and other brain compartments. Numbers indicate number of observations. (C) Overall survival analysis (Kaplan-Meier method) of patients who underwent craniotomy according to β-catenin status (high, low) and localization (nuclear, cytoplasmic); Abbreviations: OS, overall survival; TILs, tumor-infiltrating lymphocytes; p-value < 0.001***