BRD4 and Merkel cell skin cancer: Consistent with BRD4 being a transcription regulator, analysis of chromatin immunoprecipitation sequencing data revealed putative BRD4 binding sites upstream of the transcription start site of IGF2BP3 (Figure 6e), indicating a potential interaction between BRD4 and the promoter/enhancer of IGF2BP3. BRD4 expression was also positively correlated with IGF2BP3 expression in MCC (Supplementary Figure S15a).