The expression of NRP1 protein was detected and analysed in different tumour cell lines (U87, PC-3, HepG2, MCF-7, A549), and the results showed that the protein expression level of NRP1 was different in various tumour cell lines and was significantly higher in A549 cells, compared to other tumour cells (Fig.1A). The gene discussed is NRP1; the disease is neoplasm.