Protein kinase A alterations in endocrine tumors

Various molecular and cellular alterations of the cyclic adenosine monophosphate (cAMP) pathway have been observed in endocrine tumors. Since protein kinase A (PKA) is a central key component of the cAMP pathway, studies of the alterations of PKA subunits in endocrine tumors reveal new aspects of the mechanisms of cAMP pathway alterations in human diseases. So far, most alterations have been observed for the regulatory subunits, mainly PRKAR1A and to a lower extent, PRKAR2B. One of the best examples of such alteration today is the multiple neoplasia syndrome Carney complex (CNC). The most common endocrine gland manifestations of CNC are pituitary GH-secreting adenomas, thyroid tumors, testicular tumors, and ACTH-independent Cushing's syndrome due to primary pigmented nodular adrenocortical disease (PPNAD). Heterozygous germline inactivating mutations of the PKA regulatory subunit RIα gene (PRKAR1A) are observed in about two-third of CNC patients, and also in patients with isolated PPNAD. PRKAR1A is considered as a tumor suppressor gene. Interestingly, these mutations can also be observed as somatic alterations in sporadic endocrine tumors. More than 120 different PRKAR1A mutations have been found today. Most of them lead to an unstable mutant mRNA, which will be degraded by nonsense mediated mRNA decay. In vitro and in vivo functional studies are in progress to understand the mechanisms of endocrine tumor development due to PKA regulatory subunits inactivation. PRKAR1A mutations stimulate in most models PKA activity, mimicking in some way cAMP pathway constitutive activation. Cross-talks with other signaling pathways summarized in this review have been described and might participate in endocrine tumorigenesis.

Reproducibility and performance of one or two samples of salivary cortisol in the diagnosis of Cushing's syndrome using an automated immunoassay system

The purpose of this article is to evaluate the variability and reproducibility of late night salivary cortisol (LNSC) using electrochemiluminescence immunoassay (ECLIA) and compare the accuracy of one or two samples in diagnosis of Cushing's syndrome (CS). We prospectively included 64 healthy volunteers (HV), 35 patients with clinically suspected CS (S), and 26 patients with confirmed CS. Nine patients in the CS group had 24-h urinary free cortisol (UFC) less than two times the upper limit of normal (mild CS). UFC and two consecutive LNSC (LNSC1, LNSC2) were collected at home. All patients in the S group had normal UFC and low-dose dexamethasone suppression test. No differences were found between the HV and S groups in UFC, LNSC1, and LNSC2. Intra-individual variability between the two samples of LNSC was 22% in HV (1.6-91%), 32% in the S group (1.6-144%), and 51% (1.6-156%) in the CS group. Variability was higher in CS patients than those in the HV (P < 0.001) and S groups (P = 0.05). The AUC of LNSC1 was 0.945 (IC 95% 0.880-1.004); when considering the highest LNSC, the AUC was 0.980 (IC 95% 0.954-1.007) (P < 0.01). We found 23% of discordant LNSC in the S group and 11% in the CS group. Three patients with CS had only one elevated LNSC, all of them with mild CS. Our results suggest that LNSC is variable, and reproducibility is affected in both CS and S patients. We found significant improvements in the diagnostic accuracy of the LNSC measurement by obtaining two samples.

Gene expression profiling in adrenocortical neoplasia

Transcriptome studies of adrenocortical tumors have shown clear differences between adenomas and carcinomas and identified two subgroups of carcinomas with different prognoses. This review focuses on how transcriptomes have enriched our knowledge about genes previously identified by classical candidate gene approaches, uncovered novel genes relevant to adrenocortical tumor biology, helped to identify and understand specific pathway alterations, and advanced the overall translational relevance of this field of research.

Risk factors for conversion and complications after unilateral laparoscopic adrenalectomy

BACKGROUND

Laparoscopic adrenalectomy (LA) is the procedure of choice for surgical management of most benign adrenal tumours, with a reported overall complication rate around 10 per cent. The aim of this study was to determine predictive factors for postoperative complications and conversion to open surgery after unilateral LA.

METHODS

From 1994 to 2009, consecutive patients undergoing unilateral LA by the lateral transabdominal approach were analysed from a prospectively maintained database. A mass larger than 12 cm in diameter and suspected primary adrenal carcinoma were considered contraindications to LA. Predictive factors for postoperative complications and conversion to open surgery were analysed.

RESULTS

Some 462 patients were analysed. There were no postoperative deaths. Postoperative complications occurred in 53 patients (11·5 per cent), medical complications in 28, and surgical complications in 33 patients. Six patients underwent reoperation for complications. Multivariable logistic regression analysis showed that conversion to open surgery (odds ratio (OR) 6·20, 95 per cent confidence interval 2·08 to 18·53; P = 0·001) and left-sided tumour (OR 1·89, 1·02 to 3·52; P = 0·044) were independent predictive factors for overall complications. Conversion to open surgery was the only independent predictive factor for medical complications (OR 12·88, 4·21 to 39·41; P = 0·001), and left-sided LA was the only predictive factor for surgical complications (OR 2·22, 1·01 to 4·89; P = 0·047). No factor was predictive of conversion to open surgery.

CONCLUSION

In this single-institution study, conversion to open surgery and left-sided tumours were independent predictive factors for overall complications, but none of the variables analysed was predictive of conversion.

Carney complex: Clinical and genetic 2010 update

First described in the mid 1980s, Carney complex is a rare dominantly heritable multiple endocrine neoplasia syndrome that affects endocrine glands as the adrenal cortex, the pituitary and the thyroid. It is associated with many other nonendocrine tumors, including cardiac myxomas, testicular tumors, melanotic schwannoma, breast myxomatosis, and abnormal pigmentation or myxomas of the skin. The Carney complex gene 1 was identified 10 years ago as the regulatory subunit 1A of protein kinase A (PRKAR1A) located at 17q22-24. An inactivating heterozygous germ line mutation of PRKAR1A is observed in about two-thirds of Carney complex patients. This last decade many progresses have been done in the knowledge of this rare disease and its genetics. This review outlines the current state of this knowledge on Carney complex.

Evaluation of a standardized protocol for processing adrenal tumor samples: preparation for a European adrenal tumor bank

Storage and tissue handling of surgical tumor specimen have been recognized as critical steps that can potentially affect reproducibility and comparability of molecular endpoints between laboratories. In the preparation of adrenal tumor tissue banking, three different protocols that simulate warm ischemia upon tumor removal (protocol I), thawing and refreezing cycles (protocol II), as well as storage of vital tumor samples (protocol III) were applied. For the first two protocols, samples were subdivided and either snap frozen or treated with a RNA preserving agent (RPA) while in protocol III different storage media were compared. Following these procedures, recovery and integrity of DNA, RNA, and protein by means of pulsed field electrophoresis, long-range PCR, real-time PCR, immunoblot, and immunohistochemistry (protocol I and II) as well as cell viability and steroidogenic capacity (protocol III) were investigated. While DNA integrity was not influenced by different treatment modalities, expression levels of adrenal marker genes were more affected in samples after snap freezing in comparison to RPA pretreatment. Moreover, storage at room temperature before and after freezing could be demonstrated to decrease the relative amount of protein phosphorylation (ERK) and enzymatic activity (succinate cytochrome c reductase) while overall protein levels were not significantly affected. Similarly, morphological or immunohistochemical evaluation was comparable between groups. For primary cell cultures generated after storage of tumor samples similar rates of viability were observable while steroid output varied between the groups. Overall, on the basis of the presented endpoints standardized operational procedures can be defined for a proposed European adrenal tumor biobank.

Increased arterial pressure is not predictive of haemodynamic instability in patients undergoing adrenalectomy for phaeochromocytoma

BACKGROUND

Pre-operative hypotensive drugs are assumed to have dramatically decreased operative mortality and morbidity in patients undergoing phaeochromocytoma removal only in non-controlled studies. We evaluated the predictive value of pre-operative high systolic arterial pressure (SAP) on intra- and post-operative haemodynamic instability, in 96 patients undergoing laparoscopic adrenalectomy for phaeochromocytoma.

METHODS

Ninety-six consecutive patients underwent laparoscopic adrenalectomy for phaeochromocytoma. Pre-operative SAP was not systematically normalised, provided that increased SAP was clinically tolerated. Intravenous nicardipine, esmolol and norepinephrine were intraoperatively titrated to treat SAP increase >150 mmHg, tachycardia >90-110/min, arrhythmia or SAP decrease under 90 mmHg, respectively. Volume expanders were not systematically administered. Patients with increased and normal pre-operative SAP were compared with respect to (a) nicardipine, esmolol and norepinephrine requirement, (b) highest intraoperative SAP and heat rate, (c) lowest intraoperative SAP, (d) duration of surgery and (e) norepinephrine requirement following tumour removal.

RESULTS

Groups did not differ significantly with respect to data defined as being indicative of perioperative haemodynamic instability (all P values>0.05).

DISCUSSION

As previously demonstrated, in patients undergoing phaeochromocytoma removal, perioperative haemodynamic changes are mainly due to catecholamine release during tumour manipulation, and to the decrease in catecholamine level following tumour removal. Whether pre-operative hypotensive drugs are likely to alter these changes remains questionable.

CONCLUSION

For most patients scheduled for laparoscopic phaeochromocytoma removal, surgery can be carried out without systematic pre-operative arterial pressure normalisation.

Treatment of pituitary-dependent Cushing's disease with the multireceptor ligand somatostatin analog pasireotide (SOM230): a multicenter, phase II trial

CONTEXT

There is currently no medical therapy for Cushing's disease that targets the pituitary adenoma. Availability of such a medical therapy would be a valuable therapeutic option for the management of this disorder.

OBJECTIVE

Our objective was to evaluate the short-term efficacy of the novel multireceptor ligand somatostatin analog pasireotide in patients with de novo, persistent, or recurrent Cushing's disease.

DESIGN

We conducted a phase II, proof-of-concept, open-label, single-arm, 15-d multicenter study.

PATIENTS

Thirty-nine patients with either de novo Cushing's disease who were candidates for pituitary surgery or with persistent or recurrent Cushing's disease after surgery without having received prior pituitary irradiation.

INTERVENTION

Patients self-administered sc pasireotide 600 microg twice daily for 15 d.

MAIN OUTCOME MEASURE

Normalization of urinary free cortisol (UFC) levels after 15 d treatment was the main outcome measure.

RESULTS

Of the 29 patients in the primary efficacy analysis, 22 (76%) showed a reduction in UFC levels, of whom five (17%) had normal UFC levels (responders), after 15 d of treatment with pasireotide. Serum cortisol levels and plasma ACTH levels were also reduced. Steady-state plasma concentrations of pasireotide were achieved within 5 d of treatment. Responders appeared to have higher pasireotide exposure than nonresponders.

CONCLUSIONS

Pasireotide produced a decrease in UFC levels in 76% of patients with Cushing's disease during the treatment period of 15 d, with direct effects on ACTH release. These results suggest that pasireotide holds promise as an effective medical treatment for this disorder.

Massive postoperative ascites following pancreatic cysts fenestration in a patient with von Hippel-Lindau disease

Pancreatic lesions in von Hippel Lindau disease (VHLD) are frequent and mainly consist of cystic lesions, which should not be resected because of their benign evolution. Solid lesions, mostly pancreatic endocrine tumors (PET), are rare and usually occur in combination with cystic lesions. We report a case of a patient with VHLD who underwent PET enucleation in a polycystic pancreas requiring fenestration of multiple adjacent cysts, to ensure complete resection with free resection margins. The postoperative course was complicated by massive ascitic fluid effusion, probably related to pancreatic-cyst fenestration. Although this complication is well-known after liver-cyst fenestration, it has not been reported after pancreatic-cyst fenestration. This observation emphasizes that morbidity from surrounding pancreatic polycystic disease should not be underestimated in pancreatic surgery for VHLD.

Treatment of adrenocorticotropin-dependent Cushing's syndrome: a consensus statement

OBJECTIVE

Our objective was to evaluate the published literature and reach a consensus on the treatment of patients with ACTH-dependent Cushing's syndrome, because there is no recent consensus on the management of this rare disorder.

PARTICIPANTS

Thirty-two leading endocrinologists, clinicians, and neurosurgeons with specific expertise in the management of ACTH-dependent Cushing's syndrome representing nine countries were chosen to address 1) criteria for cure and remission of this disorder, 2) surgical treatment of Cushing's disease, 3) therapeutic options in the event of persistent disease after transsphenoidal surgery, 4) medical therapy of Cushing's disease, and 5) management of ectopic ACTH syndrome, Nelson's syndrome, and special patient populations.

EVIDENCE

Participants presented published scientific data, which formed the basis of the recommendations. Opinion shared by a majority of experts was used where strong evidence was lacking.

CONSENSUS PROCESS

Participants met for 2 d, during which there were four chaired sessions of presentations, followed by general discussion where a consensus was reached. The consensus statement was prepared by a steering committee and was then reviewed by all authors, with suggestions incorporated if agreed upon by the majority.

CONCLUSIONS

ACTH-dependent Cushing's syndrome is a heterogeneous disorder requiring a multidisciplinary and individualized approach to patient management. Generally, the treatment of choice for ACTH-dependent Cushing's syndrome is curative surgery with selective pituitary or ectopic corticotroph tumor resection. Second-line treatments include more radical surgery, radiation therapy (for Cushing's disease), medical therapy, and bilateral adrenalectomy. Because of the significant morbidity of Cushing's syndrome, early diagnosis and prompt therapy are warranted.

Identification of a clinically homogenous subgroup of benign cortisol-secreting adrenocortical tumors characterized by alterations of the protein kinase A (PKA) subunits and high PKA activity

OBJECTIVE

The cAMP/protein kinase A (PKA) pathway plays an important role in endocrine tumorigenesis. PKA is a heterotetramer with two regulatory subunits (four genes: PRKAR1A, PRKAR1B, PRKAR2A, PRKAR2B) and two catalytic subunits. Inactivating PRKAR1A mutations have been observed in Carney complex and a subset of adrenocortical tumors (ACT). This study was designed to search for other alterations of PKA in ACT, and to establish their correlation with the clinical characteristics.

METHODS

In this study, 35 ACT (10 non-secreting adrenocortical adenomas (ACA-NS), 13 cortisol-secreting adenomas (ACA-S), and 12 malignant s (ACC)) were studied. PKA subunits were studied by western blot and RT-qPCR. The PKA activity was measured.

RESULTS

A subgroup of ACA-S with a 96% R2B protein decrease by comparison with normal adrenal (4.1%+/-4 vs 100%+/-19, P<0.001) was identified, ACA-S2 (6/13). By contrast, no differences were observed in ACC and ACA-NS. The level of R1A mRNA was decreased in ACA-S (P<0.001), but not the level of R2B mRNA. No mutation of the R2B gene was detected in ACA-S2. The ACA-S2 group with loss of R2B protein showed a threefold higher basal PKA activity than the ACA with normal R2B protein (3.37+/-0.31 vs 1.00+/-0.20, P<0.0001). The ACA-S2 tumors with the loss of the R2B protein presented a homogenous phenotype and were all small benign cortisol-secreting tumors.

CONCLUSION

This loss of PRKAR2B protein due to a post-transcriptional mechanism in ACA-S is a new mechanism of cAMP pathway dysregulation in adrenocortical tumorigenesis. It defines a new subtype of secreting adenomas with high basal PKA activity presenting a homogenous clinical phenotype.

Phosphodiesterase 11A expression in the adrenal cortex, primary pigmented nodular adrenocortical disease, and other corticotropin-independent lesions

A variety of adrenal tumors and bilateral adrenocortical hyperplasias (BAH) leading to Cushing syndrome (CS) may be caused by aberrant cAMP signaling. We recently identified patients with a micronodular form of BAH that we have called "isolated micronodular adrenocortical disease" (iMAD) in whom CS was associated with inactivating mutations in phosphodiesterase (PDE) 11A ( PDE11A). In the present study, we examined PDE11A expression in normal adrenocortical tissue, sporadic tumors, and hyperplasias without PDE11A mutations, and primary pigmented nodular adrenocortical disease (PPNAD) and adenomas from patients with PRKAR1A and a single tumor with a GNAS mutation. The total number of the tumor samples that we studied was 22. Normal human tissues showed consistent PDE11A expression. There was variable expression of PDE11A in sporadic adrenocortical hyperplasia or adenomas; PPNAD tissues from patients with PRKAR1A mutations expressed consistently high levels of PDE11A in contrast to adenomas caused by GNAS mutations. Phosphorylated CREB was the highest in tissues from patients with iMAD compared to all other forms of BAH and normal adrenal tissue. We conclude that PDE11A is expressed widely in adrenal cortex. Its expression appears to be increased in PPNAD but varies widely among other adrenocortical tumors. PRKAR1A expression appears to be higher in tissues with PDE11A defects. Finally, sequencing defects in PDE11A are associated with a high state of CREB phosphorylation, just like PRKAR1A mutations. These preliminary data suggest that these two molecules are perhaps regulated in a reverse manner in their control of cAMP signaling in adrenocortical tissues.

Expression of vasopressin receptors in ACTH-independent macronodular bilateral adrenal hyperplasia causing Cushing's syndrome: molecular, immunohistochemical and pharmacological correlates

Cortisol secretion in ACTH-independent macronodular adrenal hyperplasia (AIMAH) causing Cushing's syndrome can be controlled by illegitimate receptors. The aim of the present study was to characterize the molecular, immunohistochemical, and pharmacological profiles of vasopressin receptors in cells derived from three patients with AIMAH (H1-H3), in order to evaluate the role of ectopic vasopressin receptors in the physiopathology of hypercortisolism. Expression of mRNAs encoding the vasopressin receptor types (V(1a), V(1b), and V(2)) were analyzed by RT-PCR in adrenal tissues. The presence of V(1a) and V(2) receptors was studied by immunohistochemistry on adrenal sections. The pharmacological profiles of vasopressin receptors involved in the control of cortisol secretion were investigated using the V(1a) receptor antagonist SR49059 and the V(2) receptor agonist [deamino-Cys(1), Val(4), D-Arg(8)]-vasopressin on cultured cells. The V(1a) receptor protein was present and functional in H1 and H3 tissues, whereas the V(1b) receptor was not expressed in any of the tissues. RT-PCR experiments revealed that V(2) receptor mRNAs were detected in the three tissues. In contrast, immunohistochemical and cell incubation studies showed that the V(2) receptor was involved in the stimulatory effect of AVP on cortisol secretion in H1 and H2, but not in H3 cells. Taken together, these data show that expression of functional ectopic V(2) receptors and repression of eutopic V(1a) receptor can coexist in some hyperplastic corticosteroidogenic tissues. They also reveal that immunohistochemical and incubation studies are essential for the characterization of ectopic receptors actually involved in the control of cortisol secretion by AIMAHs.

[Pregnancy and thyroid disorders]

Association between pregnancy and thyroid disorders is a frequent event. In case of maternal hyperthyroidism, strict guidelines relying mainly on foetal thyroid monitoring echographic scanning will allow in most cases the delivery of a healthy euthyroid newborn. Hypothyroidia, providing an adequate substitution has no significant impact on pregnancy, biological monitoring is the key of monitoring. Iodine deficiency is a matter of concern when considering neurodevelopmental outcome, however it is still an unsolved issue in France. However involvement of a multidisciplinary team is of good practice in most of the cases.

Clinical characterization of familial isolated pituitary adenomas

CONTEXT

Familial pituitary adenomas occur rarely in the absence of multiple endocrine neoplasia type 1 (MEN1) and Carney complex (CNC).

OBJECTIVE

Our objective was to characterize the clinical and genealogical features of non-MEN1/CNC familial isolated pituitary adenomas (FIPA).

DESIGN AND SETTING

We conducted a retrospective study of clinical and genealogical characteristics of FIPA cases and performed a comparison with a sporadic population at 22 university hospitals in Belgium, Italy, France, and The Netherlands.

RESULTS

Sixty-four FIPA families including 138 affected individuals were identified [55 prolactinomas, 47 somatotropinomas, 28 nonsecreting adenomas (NS), and eight ACTH-secreting tumors]. Cases were MEN1/PRKAR1A-mutation negative. First-degree relationships predominated (75.6%) among affected individuals. A single tumor phenotype occurred in 30 families (homogeneous), and heterogeneous phenotypes occurred in 34 families. FIPA cases were younger at diagnosis than sporadic cases (P = 0.015); tumors were diagnosed earlier in the first vs. the second generation of multigenerational families. Macroadenomas were more frequent in heterogeneous vs. homogeneous FIPA families (P = 0.036). Prolactinomas from heterogeneous families were larger and had more frequent suprasellar extension (P = 0.004) than sporadic cases. Somatotropinomas occurred as isolated familial somatotropinoma cases and within heterogeneous FIPA families; isolated familial somatotropinoma cases represented 18% of FIPA cases and were younger at diagnosis than patients with sporadic somatotropinomas. Familial NS cases were younger at diagnosis (P = 0.03) and had more frequently invasive tumors (P = 0.024) than sporadic cases.

CONCLUSIONS

Homogeneous and heterogeneous expression of prolactinomas, somatotropinomas, NS, and Cushing's disease can occur within families in the absence of MEN1/CNC. FIPA and sporadic cases have differing clinical characteristics. FIPA may represent a novel endocrine neoplasia classification that requires further genetic characterization.