p21, p27 and c-myc expression in the colon of Muc2−/−, p21+/+, Muc2−/−, p21+/−, or Muc2−/−, p21−/− mice. a–c: Relative level of mRNA of p21 (a), p27(b), and c-myc (c) in the colon, assayed by quantitative real-time reverse transcriptase-polymerase chain reaction. The value shown in the bars represents the mean ± SE of five different mice per group. d: Protein expression of p21, p27, and c-myc, assayed by Western blot. The quantification of p27 (e) and c-myc (f) protein were normalized to β-actin. *P < 0.05 in comparison to Muc2−/−, p21+/+ mice by Mann-Whitney test.