Through this mechanism, BRCA1 promotes translesion DNA synthesis and progression of the cell cycle.48,49 Taken together, these findings suggest that BRCA1 mRNA upregulation with PCNA could have an important role in HPV + tumours of oropharynx and in chemo-radioresistance of these patients, by promoting translesion DNA synthesis and cell-cycle progression, changing its classical function as tumour suppressor to an oncogene, as already reported in cancer stem cell models of different kinds of tumours.50 This evidence concerns the gene BRCA1 and cancer.