In order to identify whether other small molecule CDK inhibitors elicited the same KRAS selective effects as AZD5438, we assessed the tumour cell inhibitory effects of a range of CDK inhibitors: (i) AT7519, a CDK1/2/4/5/9 inhibitor [41]; (ii) dinaciclib, a CDK1/2/5/9 inhibitor [42]; and as a control (iii) PD023309, a CDK4/6 inhibitor [43], in a panel of CRC non-isogenic tumour cell lines (Fig 7 and S10 Fig). This evidence concerns the gene CDK4 and colorectal carcinoma.