Pancreatic intraepithelial neoplasia (PanIN) is a premalignant lesion that can progress to pancreatic ductal adenocarcinoma, a highly lethal malignancy marked by its late stage at clinical presentation and profound drug resistance. Here we developed novel fluorescent reporter mice that show that the stem cell determinant, Musashi (Msi) is a critical element of pancreatic cancer progression. These reporters allowed functional and image based tracking of stem cell signals within cancers in vivo, revealing that Msi expression rises as PanINs progress to adenocarcinoma, and that Msi reporter+ tumor cells are the key drivers of pancreatic cancer. To visualize and track the function of live Msi-expressing cells in vivo, we developed Msi knock-in reporters in which fluorescent signals reflected endogenous Msi expression. This dataset represents pancreatic cancer_wt and pancreatic cancer_KO cells. Three wt reps and three KO reps.