Somatostatin receptors subtypes 2 and 5, dopamine receptor type 2 expression and gsp status as predictors of octreotide LAR responsiveness in acromegaly.
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.


METHODS
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.
Vieira Neto
Leonardo
L
Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, RJ, Brazil.
Taboada
Giselle Fernandes
GF
Gadelha
Mônica Roberto
MR
D000172:Acromegaly / Q000188:drug therapy / Q000378:metabolism*; D000236:Adenoma / Q000188:drug therapy* / Q000473:pathology; D000328:Adult; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D005260:Female; D015870:Gene Expression; D006801:Humans; D008297:Male; D015282:Octreotide / Q000627:therapeutic use*; D009857:Oncogenes / Q000187:drug effects / Q000235:genetics; D010911:Pituitary Neoplasms / Q000188:drug therapy / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000235:genetics*; D017481:Receptors, Somatostatin / Q000235:genetics*
D018931:Antineoplastic Agents, Hormonal; D012333:RNA, Messenger; D017448:Receptors, Dopamine D2; D017481:Receptors, Somatostatin; C094573:somatostatin receptor 5; C093733:somatostatin receptor 2; D015282:Octreotide