EP300 and neoplasm: Given our new results showing that the fusion J-PKAc phosphorylates β-catenin at Ser675 and promotes the formation of β-catenin-TCF4-p300 complexes (Figure 11F), it is likely that the fusion kinase is involved in tumor initiation and might contribute to the development of lung metastases in fusion-positive HBL/HCN-NOS patients.