They revealed that non-cancerous cell lines express high levels of Foxo3, Foxo3P, and circ-Foxo3 compared to cancer cells, whereas transfection of Foxo3, Foxo3P, and circ-Foxo3 into MDA-MB-231 cells, triple-negative breast cancer (TNBC) cells, significantly decreased proliferation and survival of cancer cells. This evidence concerns the gene FOXO3 and cancer.