HES5 and cancer: Nevertheless, the overall expression of wild-type PTGFRN, NOTCH2 and its targets (PTCRA, HES1, HES5) are less affected in cancer (Table S6), indicating that 1) the PTGFRN-NOTCH2 fusion could occur in a subset of cancer cells or 2) that the fusion is heterozygous in cancer tissue and the fusion allele might be expressed at an extremely lower level.