The present study also found that NRP1 expression was positively correlated with the depth of tumor invasion (thickness ≤2.00) and ulceration of primary melanoma lesions, which is in accordance with other studies, showing that overexpression of NRP1 is correlated with tumor growth and metastasis in other types of cancer, thereby influencing tumor progression (25,27). This evidence concerns the gene NRP1 and melanoma.