CCND1 and gastric cancer: Function of dominant negative EGFR shows that dominant negative EGFR induces G0/G1 arrest by decreasing the expression of phosphorylated retinoblastoma protein, phosphorylated GSK-3β, CCND1, and by increasing expression of p21 and p27 in human gastric cancer cells SGC-7901 and NCI-N87 [37].