RPS6KB1 and breast cancer: Interestingly, treatment with 1,25(OH)2D3 or its analogs is able to suppress this pathway in multiple cell types, including BC cells, resulting in decreased phosphorylation of the PI3K/Akt/mTOR-downstream targets P70S6K and 4E-BP1, thereby inhibiting ribosomal translation and protein synthesis (44–47).