GJB1 and lip and oral cavity carcinoma: In another study, the downregulation of Cx43 and Cx32 expression was observed in keratocystic odontogenic tumours, one of the most frequently occurring types of benign odontogenic tumours.125 In addition to studies of changes in Cx43 and Cx32 expression during carcinogenesis, Cx26 expression was also reported to be reduced in tongue carcinoma.126,127 Recently, many studies have focused on therapies that restore connexin-mediated GJIC in oral cancer.