Bcl-xL expression levels are enhanced gradually from PanIN-1 to PDAC in P-KrasG12D mice. (A–C) P-KrasG12D mice (Pdx1-Cre; LSL-KrasG12D) (n = 12 at 2 mo, 10 at 4 mo, 6 at 7 mo, and 9 at 12–14 mo) or wild-type littermates (Pdx1-Cre) (n = 10 at 2 mo, 6 at 4 mo, 4 at 7 mo, and 10 at 12–14 mo) were killed at the indicated months. (A) Representative pictures of H&E staining. Scale bar: 100 μm (original magnification, ×200). (B) The percentage of normal pancreas in defined area. *P < .05. (C) The number of PanINs per defined area in the pancreas sections of P-KrasG12D mice. (D) Representative images of Bcl-xL immunohistochemical staining of pancreas sections in wild-type mice and P-KrasG12D mice at 12–14 months. Scale bar: 100 μm (original magnification, ×200 in the upper row and ×400 in the lower row; width of insets: 50 μm). (E) Total score for the immunostaining of Bcl-xL in normal pancreatic ducts from wild-type mice (n = 5) and PanINs/PDAC from P-KrasG12D mice at 12–14 months (n = 5). (F) Western blot of anti-apoptotic Bcl-2 family proteins in the pancreas of P-KrasG12D mice.