To recapitulate the molecular signatures of ESCC in human patients, we utilized genetic alleles for conditional knock-in of KrasG12D (cell-type-specific, constitutively active form of Kras)22 or knockout of p5323 or Pten24 (cell-type-specific, p53 or Pten loss of function). The gene discussed is PTEN; the disease is esophageal squamous cell carcinoma.