SOX2 and nestin immunoreactivity in human melanoma. (a) Spindle cell morphology in part of a biphasic (spindle and epithelioid) melanoma [haematoxilin and eosin (H&E), ×40]. (b) The spindle cell component is immunoreactive for nestin (nestin, ×40). (c, d) The pattern of nestin immunoreactivity is predominantly peripheral (c: H&E, ×200; d: nestin, ×400; inset: ×1000). (e) Cells with peripheral immunoreactivity for nestin show nuclear SOX2 positivity (SOX2, ×200; inset: ×400). (f, g) Epithelioid cell morphology in part of a biphasic (spindle and epithelioid) melanoma (f: H&E, ×40; g: nestin, ×40). (h, i) The epitheliod cell component is also immunoreactive for nestin, but the pattern of immunoreactivity is diffuse cytoplasmic (h: H&E, ×200; i: nestin, ×200; inset: ×1000). (j) Cells with diffuse cytoplasmic immunoreactivity for nestin are negative for SOX2 (SOX2, ×200).