PDX1 and neoplasm: Because Pdx1-Cre, Lkb1flox/+ (LC) mice did not develop any disease, and Pdx1-Cre Lkb1flox/flox (LLC) mice developed pancreatic tumors with a very short latency, we wondered whether the tumor phenotype we observed in Pdx1-Cre, KrasG12D/+, Lkb1flox/+ (KLC) mice was a result of complete loss of Lkb1 by loss of heterozygosity.