GJA1 and lip and oral cavity carcinoma: Connexins may be associated with cell growth, since the absence of GJIC can result in an accumulation of growth factors in cells117 and a suppression of contact inhibition, which together lead to cell proliferation.118 In addition, a decrease in Cx43 and Cx32 expression may result in the uncontrolled proliferation and abnormal differentiation of various benign and malignant tumour cells.119–121 Oral squamous cell carcinoma (OSCC) is the most prevalent and most commonly studied oral cancer.122 However, the potential role of the oral microbiome in OSCC has not been clearly elucidated.