Saeger and colleagues proposed to delineate all differentiated pituitary tumors with Ki-67 ≥ 50% and TP53 mutation as PitNET G3, and all undifferentiated/poorly differentiated tumors as PitNEC, as well as abandoning the requirement for metastasis before considering a tumor as being overtly malignant [10]. The gene discussed is TP53; the disease is neoplasm.