EGFR and neoplasm: The analysis demonstrated that CTX-MMAE showed higher in vivo potency in the MIA PaCa-2 tumour compared to PANC-1 (kkill: 3.70 mg−1 day−1vs. 1.18 mg−1 day−1) (Table 3), which runs counter to the in vitro finding that CTX-MMAE was more potent on PANC-1 tumour cells, and the fact that PANC-1 cells have higher EGFR expression; higher target receptor expression would be expected to mediate greater internalisation of the cytotoxic payload.