NRP1 and breast cancer: Similar to observations in the plasma, breast cancer cases with advanced nodal metastasis N3 (n = 14) have higher tumor NRP-1 tissue expression compared to cases with no nodal metastasis (n = 18, p = 0.041) or N1 (n = 22, p = 0.023) disease, as indicated by both multivariate and univariate analysis (Fig. 2a and b, Table 2).