KLF5 and breast cancer: It promotes tumor growth in a variety of cancers.[56] PTBP1 is highly expressed in breast cancer and its expression is associated with a poor prognosis in patients.[57, 58] A recent study has shown that PTBP1 can bind to FOXO1 mRNA[43] and XPO1 can bind to PTBP1.[42] Our recent study revealed that FOXO1 is highly expressed in BLBC and promotes tumor growth by increasing KLF5 transcription.[40] This study revealed that XPO1 can synergistically promote the nuclear export of FOXO1 mRNA by interacting with PTBP1, ultimately leading to increased transcription of KLF5 (Figure 5).