Endocrine Abstracts

Purpose: Tumor-associated protein called as anterior gradient 2 (AGR2), which is defined particularly in breast and lung carcinomas, is involved in a variety of cellular functions such as cell migration, differentiation and proliferation. Since the role of AGR2 expression in pituitary adenomas is not well known yet, it was aimed to compare AGR2 expression in normal pituitary tissue and pituitary adenoma specimens in the study.

Material and Method: We included 44 patients’ pituitary adenoma specimens (20 female/24 male) who underwent pituitary surgery at the neurosurgery clinic between 2015 and 2017 years and 10 patients’ normal pituitary tissues (5 female/5 male) operated for any reason were included as control group. Examples were stored frozen at −80°C until the study. After RNA isolation from adenomas or pituitary tissue specimens, AGR2 gene expression was evaluated by Livak method using real-time PCR method. The results were calculated as multiples of ‘1’ by making calculations according to the control group, and AGR2 expression >1 was considered to be significantly higher than the control group. Those with AGR2 expression <1 and >1 were compared with possible related parameters. Invasiveness of adenomas is described to Hardy classification and Knosp scale.

Results: The mean age at diagnosis was 47±15 (range 20–71) years, the mean maximum tumor diameter was 28±16 (range 4–75) cm. The distribution of adenomas with AGR2 expression >1; 80% (4 of 5) in ACTH secreting adenomas, 93% (13 of 14) in GH secreting adenomas, 77% (2 of 3) in PRL secreting adenomas, 71% (10 of 14) in LH / FSH secreting adenomas, 0% (0 of 1) TSH was in secreting adenomas and 71% (5 of 7) in nonsecretory adenomas (P>0.05). The maximum tumor size was larger (P=0.043), and the tumors were more invasive (P=0.01), the tumors had higher Ki-67 labelling index (P=0.05) and in AGR2<1 group when compared with AGR >1. In addition, there was a negative correlation between AGR2 expression levels and Ki-67 labelling index (r=−0.328, P=0.029).

Conclusion: The results revealed that pituitary adenomas with weak AGR2 expression present with more aggressive behaviour. However, more adenoma tissue specimens are needed to evaluate the relation with hormonal secretion pattern and effects on clinical long term course.