CIP2A and head and neck squamous cell carcinoma: Indeed, when histological grading of HNSCC samples was taken into account, we observed that 16/19 (84.2%) of Oct4/CIP2A double positive tumors were poorly differentiated whereas only 3/19 (15.8%) of CIP2A/Oct4 double positive were well-differentiated tumors (p = 0.0029; Fig. 5C).