According to the new WHO classification of pituitary tumors from 2022, the pathologic assessment of somatotroph tumors should include immunostaining for anterior pituitary hormones, pituitary transcription factors, low-molecular-weight cytokeratins (LMWCs), proliferation markers (mitoses count, Ki-67 labeling index, and p53), and selected E-cadherin and somatostatin receptors (SSTRs) [2,3]. Here, MKI67 is linked to pituitary tumor.