Introduction: SOX2 is an early developmental transcription factor and a marker for pituitary progenitor cells.
The study aimed to investigate if the pituitary adenomas with positive SOX2 immunoreactivity shows a different response to therapy as compared with controls.
Patients and methods: We investigated 15 pituitary macroadenomas, eight with SOX2 immunoreactivity (SOX2+) and seven without (SOX2−) (controls); five were GH producing tumours (three SOX2+, two SOX2−), five prolactinomas (four SOX2+, one SOX2−) and five non-functioning pituitary tumours (one SOX2+, four SOX2−) confirmed by immunohistochemistry, ABC method. Anterior pituitary hormones were measured in simultaneously sampled serum and cerebrospinal fluid (CSF) by fluoroimmunoassay with europium. Three patients with SOX+ and three SOX− adenomas showed high CSF:serum ratio for one or two hormones (five of them for FSH and/or LH and one for prolactin). The tumour volume was appreciated by CT or MRI.
Results: All pituitary adenomas were partially removed by surgery. Additional treatment were i) high-voltage radiotherapy or gamma knife (two SOX+ and three SOX− tumours); ii) radiotherapy associated with medical treatment with somatostatin analogs and/or dopaminergic agonist cabergoline (four SOX+ and one SOX− tumours); iii) only medical treatment (one SOX+ and two SOX− tumours). The average follow-up was 53.3 months.
From first group A with radiotherapy, both SOX2+ pituitary adenomas were cured and there was upper 50% decrease in tumour volume in two SOX2− pituitary adenomas. Patients with triple therapy (B) need high doses of dopaminergic agonists and somatostatin analogs. Both, tumour volume and hormone secretion decreased when drug therapy started after radiotherapy (the tumour volume decreased more than 50% in two SOX+ and one SOX− tumour and lower than 50% in two SOX+ adenomas).
Conclusion: Pituitary macroadenomas with SOX2-positive cells are not refractory to treatment and showed similar responses to radiotherapy or/and medication (somatostatin analogues or cabergoline) as the controls.
27 Apr - 01 May 2013
European Society of Endocrinology