RT-PCR analysis of expression of Mmp9 in murine Cdkn2a-/-;p53-/- and in WT placentas on day E14.5 (n>=4 fields of view for each genotype). Values are means + SEM of at least three experimental repeats. Data information: Values are means + SEM of at least three experimental repeats. Statistical significance was determined by unpaired two-tailed Student's t-test (*) p < 0.05; (**) p < 0.01; (***) P<0.001. 