KLF4 and breast cancer: Our data on KLF4α in breast cancer mostly confirms this study with some significant novel additions and relevant differences: (i) Compared to Wei et al. [26] our sequencing analysis showed that MDA-MB-231 cells contain a KLF4 protein with nine additional N-terminal amino acids (MRQPPGESD) corresponding to the EMBL Nucleotide Sequence Database accession number HF546201.