Figure 3.

Representative immunohistochemistry of SCF or c-Kit on the same area of interest around CD31⁺ blood vessels in the normal skin (A, E, I), compound nevi (B, F, J), dysplastic nevi (C, G, K), and melanomas (D, H, L) tissue sections. The micrographs show a significative gradual increased CD31, SCF, and c-Kit expression in malignant melanoma lesions compared to premalignant ones and normal skin (A–L). The SCF- or c-Kit-positive mast cells appear mostly with a strong red-granulous membranous and moderate cytoplasmic staining in all the samples (see the inserts in the red rectangles; scale bar: 10 μm). The morphometric analysis performed on the same region of interest for all three markers confirmed an increased SCF⁺/c-Kit⁺ mast cell infiltrate around blood vessels in melanoma compared to normal skin, compound nevi, and dysplastic ones, both in percentages of immunolabeling positivity and number of positive cells (M, N). Linear regression analysis shows positive relationships between SCF or c-Kit and CD31(O), and between SCF and c-Kit (P) [(O) For SCF: y=3.698x+0.008438; R2 = 0.7048; p ≤ 0.0001. (O) For c-Kit: y=1.435x+0.004774; R2 = 0.792; p ≤ 0.0001. (P) y=2.61x-0.004682; R² = 0.9123; p ≤ 0.0001]. Data are reported as means ± SD, and Tukey post-test was used to compare all groups after one-way ANOVA. Statistical significance: ns, not significative; *p ≤ 0.05; **p ≤ 0.01; ***p ≤ 0.001; ****p ≤ 0.0001. Scale bar: 200 μm.