MKI67 and cancer: Pasquel et al. similarly reported a case of non-functioning PitNET with a Ki-67 labeling index of 30–80% [22] but no metastases, prompting them to propose a new term “carcinoma in situ.” Guo et al. reported a poorly differentiated, metastatic, corticotroph PitNET with a Ki-67 labeling index of 80%, as well as TP53, ATRX, and PTEN mutations [23].