NRP1 and head and neck squamous cell carcinoma: However, in HN13 cells, a significant difference in the IC50 between the shNRP-1 vs. pLKO cells was not appreciated, suggesting that NRP-1 might have a major impact on CDDP sensitivity in the EGFR wild-type (CAL33) and EGFR amplified (HN6) HNSCC cells (Figure 5I) (Table 2).