While gemcitabine alone does not show anti-cancer effects on endogenously developed pancreas cancer in rats (our unpublished result) or in mouse models [29], the results presented here demonstrate the usefulness of N-ERC/mesothelin as a serum marker in monitoring preclinical trials for therapy in mouse and rat models of pancreas ductal adenocarcinoma: serodiagnosis in animal models can be used to enhance screening for candidate chemotherapeutic agents that could be evaluated for human use. The gene discussed is MSLN; the disease is cancer.