PMEL and melanoma: None of the 20 cases established not to have predominantly Sox2 immunopositive tumor cells had any co-localization of Sox2 and the tumor-specific marker, ie no lymphoma cells with CD20 immunoreactivity were also Sox2-immunopositive, no carcinoma cells with CAM5.2 immunopositive cytoplasm had any nuclear Sox2 immunoreactivity, and no melanoma cells with HMB45 cytoplasmic immunopositivity had Sox2-immunoreactive nuclei (Figure 3).