POU5F1 and neoplasm: When examining the categorical values of ΔCEA (elevated vs. normal), a statistically significant association was found between elevated ΔCEA and tumor undifferentiation (p=0.008), clinical-pathological stage IIIB (p=0.006), pathological stage III (p <0.001), locally/advanced clinical stage (p=0.004), positive expression of OCT4 at the time of diagnosis (p <0.001), and negative values of ΔOCT4 (p <0.001) and ΔOCT4/GUSB (p <0.001), indicating a poor therapeutic response (Table 4).