MKRN3 and head and neck squamous cell carcinoma: Furthermore, the subgroup analysis revealed that high MKRN3 expression was an unfavorable factor for the prognosis of SCCHN patients at stages III + IV (Fig. 4a; P < 0.001) and T3 + 4 (Fig. 4b; P < 0.05), but not in the N (Fig. 4c, P  > 0.05) or M classification (Fig. 4d, P > 0.05).