CDKN1B and breast cancer: Moreover, knockdown of p27 in human BC T24 cells, T24(shp27), also resulted in a similar reduction of PHLPP2 expression (Fig. 2c), while overexpression of p27 in human BC HT1197 cells, HT1197(GFP-p27), increased PHLPP2 expression (Fig. 2d).