Fig. 4

Loss of PTEN protein expression by melanoma cells associated with a lack of CD8⁺ T cell infiltration. a Immunofluorescence demonstrates that the on-treatment specimen shows PTEN protein expression by SOX10-positive melanoma cells and CD8⁺ T cell infiltration (left panels); (b) the therapeutic-resistant post-treatment specimen (right panels) from the same patient shows minimal PTEN protein expression by SOX10-positive melanoma cells and no CD8⁺ T cell infiltration. Multiplex immunofluorescence staining was performed for DAPI, Sox10, CD8, and PTEN; each stain shown separately and merged