These results indicate that pancreatic Pbrm1 loss synergizes with oncogenic Kras and heterozygous Trp53 deletion to yield poorly differentiated PDAC or undifferentiated carcinoma of the pancreas with squamous subtype properties, and induces liver metastasis, resulting in a poor prognosis. The gene discussed is KRAS; the disease is undifferentiated pancreatic carcinoma.