Figure 4. Clinical relevance of DLK1 in somatotroph adenomas. (A) MR images of PitNET patients. (B) Transmission electron microscope of PitNET patients. (C) Immunohistochemistry image of DLK1, PIT1 and SSTR2 in PitNET patients. 400×. (D) The TPM values of DLK1, serum GH levels and tumor volumes in 31 somatotroph adenomas. (E) Correlation of DLK1 and serum GH, tumor volume. (F) There was statistic difference of GH level between patients with high DLK1 and low DLK1, not tumor volume. (G) ROC curve. HRAS (0.825), WNT5B (0.819), Notch2 (0.799), DLK1 (0.795) and ITPR2 (0.782) were filtered in PI3K/AKT/mTOR pathway, Notch pathway and growth hormone synthesis, secretion and action. *compare to control group P<0.05 **P<0.01 ***P<0.001.