In mice implanted with MIA PaCa-2 xenografts, which have a lower EGFR density than PANC-1, and a 35-fold higher IC50 for CTX-MMAE, treatment with CTX-MMAE at 0.1, 1 or 5 mg/kg led to dose-dependent inhibition of tumour growth. The gene discussed is EGFR; the disease is neoplasm.