KRAS and neoplasm: Furthermore, KRB-456 was also effective at inhibiting the viability of primary and metastatic mt KRAS tumor cells (derived from 8 patients with pancreatic cancer) in 3D cocultures with pancreatic stellate cells, precursor cells of cancer-associated fibroblasts that reside in the tumor microenvironment, and that promote tumor proliferation and metastasis as well as drug resistance.