NRP1 and nonpapillary renal cell carcinoma: Therefore, we tested the 1E9 antibodies on ccRCC (A498 and 786-O, high expression of Neuropilin 1 and Neuropilin 2) and breast (MDA-MB-231, high expression of Neuropilin 1 positive and low expression of Neuropilin 2) tumor cells.