Consistent with their pattern of genetic alterations observed in human cancers, overexpression of CHKα is oncogenic in human embryonic kidney 293T (HEK293T) or Madin-Darby canine kidney (MDCK) cells, while CHKβ overexpression is not sufficient to induce cell transformation nor in vivo tumor growth [9,12,13]. This evidence concerns the gene CHKB and cancer.