Consistent with the histologic differentiation, the M6 pituitary adenoma showed massive upregulation of POU1F1 and PITX1, high overexpression of PITX2 and NR4A1-3, but minimal or absent expression of TBX19 and NR5A1, respectively (Fig. 5F). Here, PITX2 is linked to pituitary gland adenoma.