POLE and cancer: The last decade has witnessed the identification in cancers from many tissue types of multiple somatically acquired missense mutations clustering in the sequence encoding the exonuclease proofreading domain of POLE with a high incidence in colorectal (3%) and endometrial (8%) cancers (Yoshida et al, 2011; Cancer Genome Atlas Research Network et al, 2013; Palles et al, 2013; Heitzer & Tomlinson, 2014; Shinbrot et al, 2014; Campbell et al, 2017).