PTBP1 and breast cancer: Ultimately, the authors show that NAS1 can promote the dormancy of breast cancer metastatic cells, and it does so by binding to the GC-rich 5′UTR of NR2F1 (Nuclear Receptor Subfamily 2 Group F Member 1) mRNA, recruiting the RBP PTBP1, which enhances the internal ribosome entry site-dependent translation of NR2F1, a transcription factor known to promote tumor dormancy in breast cancer [74].