RPS6KA1 and breast cancer: As a member of p90RSK family, it is closely associated with ERK, PI3K and p53 signalling pathways, as well as implicated in cell growth, survival, motility and senescence.22, 23, 24 It can mediate resistance to PI3K inhibitors in breast cancer cells both in vitro and vivo.25 It has been reported that RPS6KA6 is a prognostic factor for renal cell carcinoma (RCC) and its overexpression could promote cell cycle progression and enhance the invasive and metastatic capability of RCC cell lines26