In contrast to our results, other studies, which assessed claudin-1 semi-quantitatively via immunohistochemistry, reported an increase in claudin-1 expression in OSCC without any effect on overall survival [16] in connection with an advanced tumor stage [23], the poor [23,24] or good differentiation of oral tumor tissue [20,22,25], lymph node metastasis, and angiolymphatic and perineural invasion [23]. The gene discussed is CLDN1; the disease is neoplasm.