b, Quantification of PanIN from mice of the indicated genotype and age. Fold increase and male/female ratios are shown. Box plots express the first (Q1) and third (Q3) quartiles set by the upper and lower limits of the box, whereas the median is shown by the horizontal line inside the box. The whiskers extend upward and downward to the highest or lowest observation within the upper (Q3 + 1.5 × the interquartile range) and lower (Q1 − 1.5 × interquartile range) limits. Values outside the upper and lower limits are 'outliers' and are shown by individual symbols. 