PTK7 and pancreatic neoplasm: The differences in cell death among the three pancreatic cancer cell lines may be attributed to PTK7 protein levels, with lower PTK7 on KPC1199 cells leading to reduced uptake of VNP@Sgc8c-MMAE and consequently lower cytotoxic effects, which is in line with the results in Supplementary Fig. 3d–f and Supplementary Fig. 4c.