Meiotic recombination proteins in cancer

Although mitotic cells normally suppress the expression of proteins involved in meiosis, a series of meiotic recombination proteins are commonly expressed in cancers, outside of their normal context. Here we review mechanistic and genomic evidence linking meiotic recombination proteins to cancer, focussing on HORMAD1, SPO11, SYCP1, SYCP3, PRDM9, DMC1, HSF2BP, MEIOB, REC8, RAD21L, STAG3 and the HOP2-MND1 heterodimer. We describe how the ectopic expression of these proteins in tumours is thought to influence tumour biology through diverse mechanisms that are associated with genome stability. We also propose a Similar/Modified/Neo-function (SMN) model for how additional functions of meiotic recombination proteins in cancer might be found and how approaches to targeting tumours that express these proteins might be identified.