Elevated soluble epidermal growth factor receptor level in pituitary adenoma and carcinoma

To investigate effect of the soluble epidermal growth factor receptor (sEGFR/sErbB1) level in the peripheral blood in development, invasiveness, apoplexy of each type of pituitary tumor.

The sEGFR level was determined in peripheral serum from 190 patients with pituitary diseases by enzyme linked immunosorbent assay. The sEGFR levels were measured in 10 pituitary Rathke's pouch, 18 pituitary hyperplasia, 161 pituitary adenomas including 30 microadenomas, 83 large adenomas, 48 giant adenomas, 1 pituitary carcinoma, and 28 healthy controls.

In the patients with pituitary hyperplasia, microadenoma, large adenoma, giant adenoma, and pituitary carcinoma, the sEGFR level was 188.92 +/- 32.62, 209.83 +/- 19.01, 333.20 +/- 69.33, 405.85 +/- 37.38, and 617.45 fmol/mL independently. They were all significantly higher than patients with pituitary Rathke's pouch (156.78 +/- 18.24 fmol/mL, P < 0.001) and healthy control group (159.11 +/- 40.50 fmol/mL, P < 0.05). The sEGFR level in pituitary carcinoma was higher than pituitary adenoma. In patients with pituitary adenoma, the sEGFR level was positive correlated to the size of pituitary adenomas (r=0.998), the significant difference was observed for the sEGFR level in each group of the patients with pituitary adenomas (P < 0.001). Furthermore, in patients with pituitary ACTH-secreting microadenomas, the serum sEGFR levels in invasiveness (295.00 +/- 77.80 fmol/mL) was higher than that in non-invasiveness (210.60 +/- 16.4 fmol/mL, P < 0.05). In patients with pituitary ACTH-secreting, PRL-secreting, GH-secreting, and non-functioning large adenomas, the serum sEGFR levels in invasiveness (407.86 +/- 28.50, 399.25 +/- 30.10, 386.00 +/- 13.08, and 369.25 +/- 36.70 fmol/mL) was higher than that in non-invasiveness (335.25 +/- 63.49, 300.64 +/- 47.57, 297.00 +/- 61.93, and 269.30 +/- 25.68 fmol/mL) respectively (P < 0.05). In patients with invasive pituitary PRL-secreting, GH-secreting, and non-functioning giant adenomas, the serum sEGFR levels not significantly different in between invasiveness (417.50 +/- 35.94, 409.50 +/- 69.14, and 417.50 +/- 44.13 fmol/mL) and non-invasiveness (386.00 +/- 49.64, 417.50 +/- 44.03, and 409.51 +/- 35.17 fmol/mL) (P > 0.05). In patients with pituitary large adenomas, the sEGFR levels in pituitary apoplexy (377.48 +/- 39.18 fmol/mL) was higher than that in non-pituitary apoplexy (343.18 +/- 68.17 fmol/mL, P > 0.05).

The increased level of peripheral serum sEGFR is concomitant with development, proliferous size of the adenomas in patients with pituitary adenomas. In addition, the elevated levels of serum sEGFR occur in pituitary apoplexy as clinical active tumors, and the non-invasive ACTH secreting adenomas. The sEGFR levels could be differentiated helpfully between pituitary adenomas and non-pituitary adenomas. These data suggest that serum sEGFR could be as a referable marker of the size and activation of proliferation in pituitary adenoma.