Wang L, et al. - Data mining was utilized to investigate breast cancer (BC, the most lethal human malignancy and is the principal cause of cancer-associated death in women globally) data from The Cancer Genome Atlas (TCGA) database, which was downloaded using the UCSC Xena browser in order to determine the role of Krüppel-like factor 9 (KLF9), which belongs to a family of transcriptional regulators. It was discovered that via the various tumor-associated signaling pathways, in the carcinogenesis of BC, KLF9 plays a significant role. Moreover, the hypermethylation of KLF9 led to its decreased expression in BC, whilst in BC, it has a potential in the prognostication of favorable outcomes.