CTCF and lymphoma: Instead, PC3 was characterized by a sharp, hotspot-like mutation risk increase directly upstream of the TSS observed in skin, gastric and lymphoid cancers (Supplementary Figure S3E and Supplementary Figure S4); this is consistent with the known promoter hotspots due to UV damage in skin (19,20), with CTCF-binding site hotspots associated with SBS17 in gastrointestinal cancers (16), as well as with local SHM in lymphocytes (54).