A total of 11% of cells from degenerate and 6% of cells from non-mildly-degenerate NP tissue were positive, whereas 18% of the cells from degenerate and 10% of cells from non-mildly-degenerate AF tissues stained positive for p16INK4a (p < 0.05) (Figure 1C). This evidence concerns the gene CDKN2A and atrial fibrillation.