Initially, it was suggested that TP53 mutations occur at a late stage of carcinogenesis [30], but it has turned out that this mutation might be a founding event in gastric cancer carcinogenesis [31]; however, the activity of P53 seems to be regulated by tight junctions [32] so the overexpression of claudin-6 could be associated with higher malignancy and consequently bad prognosis. The gene discussed is CLDN6; the disease is gastric cancer.