POLB and cancer: DNA polymerase β (polβ) is a member of the DNA polymerase family and is essential for base excision repair (BER), one of the major pathways of DNA repair.17, 18, 19, 20, 21 Thirty percent of all tumours reported to date harbour mutations in the polβ gene.22 Aberrant polβ expression results in an increased rate of spontaneous mutagenesis, and a highly mutagenic phenotype.23, 24 Studies have reported polβ mutations in various cancer types, and have shown that this may play a role in mediating tumour sensitivity to cisplatin.25, 26, 27, 28, 29