NRP1 and skin neoplasm: Both in skin tumour and in glioblastoma multiforme, NRP1 was proved to promote the cell self-renewal, stemness and tumorigenicity through VEGF-VEGFR2-NRP1 axis; whereas in breast cancer, nuclear factor of kappa light polypeptide gene enhancer in B cells (NF-kappa B) pathway activation is also involved [31–33].