Kruskal-Wallis test on the NRP1 scoring pattern in the patient samples revealed that NRP1 expression increased significantly from common nevi (mean 3.1) and dysplastic nevi (mean 4.2), to primary melanoma (mean 6.7) and metastatic melanoma (mean 70; P<0.0001, CN+DN vs. PM+MM; Fig. 2B). This evidence concerns the gene NRP1 and metastatic melanoma.