Correlation between IHC expression patterns of MK and NANOG and clinicopathological features of OSCCs. (A) The enhanced expression of MK and NANOG proteins showed strong correlation with high-grade OSCC (p < 0.001), whereas weak or negative expression of the two markers is significantly correlated with a well-differentiated tumor (MK: p < 0.001; NANOG: p < 0.05); (B) in particular, co-enhanced expression of MK and NANOG is significantly correlated with moderately- or poorly-differentiated high-grade OSCC (p < 0.001). Conversely, weak or negative co-expression of MK and NANOG is predominantly detected in well-differentiated tumors (p < 0.001); (C) graphs show the enhanced expression of MK and NANOG is directly associated with late-stage tumors (stage III or IV) (p < 0.05), whereas weak or negative expression of two markers is associated with early-stage tumors (stage I or II) (p < 0.05); (D) graphs show the weak or negative expression of MK or NANOG protein associated with negative neck node metastasis (MK: p < 0.001; NANOG: p < 0.01), although the enhanced expression of two markers has no association with positive neck node metastasis (p > 0.05). Data represent the number of cases with positive expression of each protein, and asterisks indicate statistical significance (* p < 0.05; ** p < 0.01; *** p < 0.001).