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Arquivos Brasileiros de Endocrinologia & Metabologia
On-line version ISSN 1677-9487
VIEIRA NETO, Leonardo; TABOADA, Giselle Fernandes and GADELHA, Mônica Roberto. Somatostatin receptors subtypes 2 and 5, dopamine receptor type 2 expression and gsp status as predictors of octreotide LAR® responsiveness in acromegaly. Arq Bras Endocrinol Metab [online]. 2008, vol.52, n.8, pp.1288-1295. ISSN 1677-9487. http://dx.doi.org/10.1590/S0004-27302008000800014.
We present two acromegalic patients in which clinical and molecular data are discussed in regard to their ability to predict long term octreotide LAR® therapy response. Case reports: Patient 1: female, 36 years old at diagnosis. Basal GH and IGF-I at diagnosis were 133 ng/mL and 181% above the upper limit of reference values (ULRV), respectively. Growth hormone during acute test with subcutaneous octreotide decreased from 133 to 13 ng/mL. Patient started on primary octreotide LAR® therapy (20mg q28 days) and achieved biochemical parameters of disease control after 6 months. Molecular analysis of tumor fragments: gsp +; quantitative analysis of SSTR (somatostatin receptor) and DR (dopamine receptor) mRNA - SSTR2 23954; SSTR5 2407; DR2 total 17016 copies. Patient 2: male, 38 years old at diagnosis. Basal GH and IGF-I at diagnosis were 120 ng/mL and 114% ULRV, respectively. Patient underwent non-curative trans-sphenoidal surgery. Post-operative GH and IGF-I were 112 ng/mL and 137% ULRV, respectively. Growth hormone during acute test with subcutaneous octreotide decreased from 112 to 7 ng/mL. Octreotide LAR® therapy (20 mg q28 days) was then initiated. After 6 months of treatment, patient did not attain biochemical control of disease and displayed increased tumor volume. Molecular analysis of tumor fragments: gsp not done; quantitative analysis of SSTR and DR mRNA - SSTR2 416; SSTR5 3767; DR2 total 3439 copies. In conclusion, these two cases illustrate how laboratory data can be conflicting as predictors of octreotide LAR® responsiveness and how molecular analysis of tumor fragments can help explain different behaviors in clinically similar patients.
Keywords : Acromegaly; Somatostatin receptor; Dopamine receptor; Octreotide LAR®.