KRAS and pancreatic neoplasm: The allelic imbalance is not unique to pancreatic cancer and was also observed in a triple-negative breast cancer (TNBC) model that develops claudin-low (i.e., mesenchymal-like) mammary tumors in response to a mammary epithelial-specific activation of KRASG12D under the control of the endogenous KRAS locus [28].