Distinct mutational signatures were associated with: mutations in BRCA1/2 in breast and pancreatic cancers; failure of the DNA mismatch repair pathway (e.g. due to methylation of the MLH1 promoter) in colorectal cancers; hypermutation of the immunoglobulin gene in CLL; recurring polymerase ɛ mutations in uterine and colorectal cancers. Here, BRCA1 is linked to colorectal cancer.