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Dopamine receptor subtype 2 expression profile in nonfunctioning pituitary adenomas and in vivo response to cabergoline therapy
Author(s) -
Vieira Neto Leonardo,
Wildemberg Luiz Eduardo,
Moraes Aline B.,
Colli Leandro M.,
Kasuki Leandro,
Marques Nelma Verônica,
Gasparetto Emerson L.,
Castro Margaret,
Takiya Christina Maeda,
Gadelha Mônica R.
Publication year - 2015
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/cen.12684
Subject(s) - cabergoline , medicine , immunohistochemistry , adenoma , adjuvant therapy , endocrinology , pituitary adenoma , pathology , gastroenterology , urology , cancer , prolactin , hormone
Summary Objectives To determine the dopamine receptor subtype 2 (DR2) mRNA levels and protein expression and to evaluate the effect of adjuvant cabergoline therapy on tumour volume ( TV ) in patients with postoperative residual nonfunctioning pituitary adenoma ( NFPA ). Methods The mRNA expression was quantified by real‐time RT‐PCR (TaqMan ® ), and protein expression was evaluated by immunohistochemistry. Tumours were classified according to the percentage of immunostained cells for DR2 as scores 1 (<50% of stained cells) or 2 (≥50%). Cabergoline was started at least 6 months after surgery in nine patients with residual tumours (3 mg/week). The cabergoline effect was prospectively evaluated by magnetic resonance imaging using three‐dimensional volume calculation. TV reduction >25% was considered significant. Results The DR2 mRNA expression was variable but was observed in 100% of the samples ( N = 20). DR2 protein expression was also observed in all the tumours ( N = 34). Twenty‐nine tumours (85%) were classified as score 2. The median DR2 mRNA expression was higher in the tumours classified as score 2 compared with score 1 ( P = 0·007). TV reduction with cabergoline therapy was observed in 67% of the patients (6/9). The median TV before and after 6 months of treatment was 1·90 cm 3 (0·61–8·74) and 1·69 cm 3 (0·36–4·20) [ P = 0·02], respectively. Conclusion In conclusion, DR 2 is expressed in all adenomas and the majority of the patients in this study displayed tumour shrinkage on cabergoline ( CAB ) therapy. Thus, CAB might be useful in adjuvant therapy in NFPA patients with residual tumours after surgery.