PCNA and type 2 diabetes mellitus: Figure 2A,B shows that adenoviral expression of p27kip1 increased nuclear accumulation of p27kip1 in human β-cells to a frequency similar to those observed in β-cells from T2D donors. At 100 moi, 33.5 ± 3.7% of β-cells displayed p27kip1 in their nuclei, an abundance similar to that in β-cell from T2D donors (29.1 ± 4.5%) (Fig. 1E). In addition, p27 overexpression reduced the proliferation induced by the expression of cdk6 and cyclin D3 or any combination of G1/S cyclins and cdks (Fig. 2C,D).