KRAS and rectal cancer: DUSP4 upregulation has been reported in KRAS mutant rectal cancer,44 and higher DUSP4 levels have been found in melanoma cell lines compared with normal human epidermal melanocytes.45 Conversely, DUSP4 levels are higher in indolent ovarian serous borderline tumours compared with more aggressive serous carcinomas,46 and silencing of DUSP4 plays a key role in the development of glioblastomas,47 suggesting a tumour-suppressor role.