MLH1 and inflammatory bowel disease: The pathophysiology of IBD-CRC is different to sporadic CRC and is characterised by early TP53 mutations and late and infrequent APC mutations; whereas a minority of around 13–15% sporadic CRC develop defective DNA mismatch repair as a result of acquired promoter hypermethylation of the MLH1 gene that silences its expression, and these occur mostly in the right colon [27,28].