Using CRISPR/Cas9 knockout screens a multi-institutional research team systematically interrogated the essentiality of more than 10,000 forkhead box protein A1 (FOXA1) and CTCF binding sites in breast and prostate cancer cells, plucking useful needles from a massive genomic haystack that contains millions of transcription factor binding sites. They found that essential FOXA1 binding sites act […]