Figure 1

Representative examples of PIR immunohistochemical staining in a melanoma-specific TMA. (a) Nuclear staining in normal melanocytes (indicated by arrows) from a healthy skin tissue sample; (b) Primary infiltrating melanoma with low nuclear staining; (c) Mixed nuclear and cytoplasmic staining in an intra-epidermal melanoma; (d) Intense staining both in the nucleus and in the cytoplasm in metastatic melanoma; (e) strong exclusive cytoplasmic staining in metastatic melanoma. To detect immunoreactions VECTOR VIP was used as peroxidase substrate in order to optimize differences between between the reaction product (purple) and background melanin. Original magnification 400× for a, and 200× for b-e, scale bar 100 μm. Insets show 400× magnification. (f) Quantitative analysis of PIR subcellular distribution in the TMA among Radial Growth Phase (RGP), Vertical Growth Phase (VGP) and Metastatic Melanoma (MM); Clark level is indicated.