A new prognostic clinicopathological classification of pituitary adenomas: a multicentric case-control study of 410 patients with 8 years post-operative follow-up

Pituitary adenomas are currently classified by histological, immunocytochemical and numerous ultrastructural characteristics lacking unequivocal prognostic correlations. We investigated the prognostic value of a new clinicopathological classification with grades based on invasion and proliferation. This retrospective multicentric case-control study comprised 410 patients who had surgery for a pituitary tumour with long-term follow-up. Using pituitary magnetic resonance imaging for diagnosis of cavernous or sphenoid sinus invasion, immunocytochemistry, markers of the cell cycle (Ki-67, mitoses) and p53, tumours were classified according to size (micro, macro and giant), type (PRL, GH, FSH/LH, ACTH and TSH) and grade (grade 1a: non-invasive, 1b: non-invasive and proliferative, 2a: invasive, 2b: invasive and proliferative, and 3: metastatic). The association between patient status at 8-year follow-up and age, sex, and classification was evaluated by two multivariate analyses assessing disease- or recurrence/progression-free status. At 8 years after surgery, 195 patients were disease-free (controls) and 215 patients were not (cases). In 125 of the cases the tumours had recurred or progressed. Analyses of disease-free and recurrence/progression-free status revealed the significant prognostic value (p < 0.001; p < 0.05) of age, tumour type, and grade across all tumour types and for each tumour type. Invasive and proliferative tumours (grade 2b) had a poor prognosis with an increased probability of tumour persistence or progression of 25- or 12-fold, respectively, as compared to non-invasive tumours (grade 1a). This new, easy to use clinicopathological classification of pituitary endocrine tumours has demonstrated its prognostic worth by strongly predicting the probability of post-operative complete remission or tumour progression and so could help clinicians choose the best post-operative therapy.

Clinical characteristics and therapeutic responses in patients with germ-line AIP mutations and pituitary adenomas: an international collaborative study

CONTEXT

AIP mutations (AIPmut) give rise to a pituitary adenoma predisposition that occurs in familial isolated pituitary adenomas and less often in sporadic cases. The clinical and therapeutic features of AIPmut-associated pituitary adenomas have not been studied comprehensively.

OBJECTIVE

The objective of the study was to assess clinical/therapeutic characteristics of AIPmut pituitary adenomas.

DESIGN

This study was an international, multicenter, retrospective case collection/database analysis.

SETTING

The study was conducted at 36 tertiary referral endocrine and clinical genetics departments.

PATIENTS

Patients included 96 patients with germline AIPmut and pituitary adenomas and 232 matched AIPmut-negative acromegaly controls.

RESULTS

The AIPmut population was predominantly young and male (63.5%); first symptoms occurred as children/adolescents in 50%. At diagnosis, most tumors were macroadenomas (93.3%); extension and invasion was common. Somatotropinomas comprised 78.1% of the cohort; there were also prolactinomas (n = 13), nonsecreting adenomas (n = 7), and a TSH-secreting adenoma. AIPmut somatotropinomas were larger (P = 0.00026), with higher GH levels (P = 0.00068), more frequent extension (P = 0.018) and prolactin cosecretion (P = 0.00023), and occurred 2 decades before controls (P < 0.000001). Gigantism was more common in the AIPmut group (P < 0.000001). AIPmut somatotropinoma patients underwent more surgical interventions (P = 0.00069) and had lower decreases in GH (P = 0.00037) and IGF-I (P = 0.028) and less tumor shrinkage with somatostatin analogs (P < 0.00001) vs. controls. AIPmut prolactinomas occurred generally in young males and frequently required surgery or radiotherapy.

CONCLUSIONS

AIPmut pituitary adenomas have clinical features that may negatively impact treatment efficacy. Predisposition for aggressive disease in young patients, often in a familial setting, suggests that earlier diagnosis of AIPmut pituitary adenomas may have clinical utility.

Imprinting of the G(s)alpha gene GNAS1 in the pathogenesis of acromegaly

Approximately 40% of growth hormone-secreting pituitary adenomas have somatic mutations in the GNAS1 gene (the so-called gsp oncogene). These mutations at codon 201 or codon 227 constitutively activate the alpha subunit of the adenylate cyclase-stimulating G protein G(s). GNAS1 is subject to a complex pattern of genomic imprinting, its various promoters directing the production of maternally, paternally, and biallelically derived gene products. Transcripts encoding G(s)alpha are biallelically derived in most human tissues. Despite this, we show here that in 21 out of 22 gsp-positive somatotroph adenomas, the mutation had occurred on the maternal allele. To investigate the reason for this allelic bias, we also analyzed GNAS1 imprinting in the normal adult pituitary and found that G(s)alpha is monoallelically expressed from the maternal allele in this tissue. We further show that this monoallelic expression of G(s)alpha is frequently relaxed in somatotroph tumors, both in those that have gsp mutations and in those that do not. These findings imply a possible role for loss of G(s)alpha imprinting during pituitary somatotroph tumorigenesis and also suggest that G(s)alpha imprinting is regulated separately from that of the other GNAS1 products, NESP55 and XLalphas, imprinting of which is retained in these tumors.

Gigantism and acromegaly due to Xq26 microduplications and GPR101 mutation

BACKGROUND

Increased secretion of growth hormone leads to gigantism in children and acromegaly in adults; the genetic causes of gigantism and acromegaly are poorly understood.

METHODS

We performed clinical and genetic studies of samples obtained from 43 patients with gigantism and then sequenced an implicated gene in samples from 248 patients with acromegaly.

RESULTS

We observed microduplication on chromosome Xq26.3 in samples from 13 patients with gigantism; of these samples, 4 were obtained from members of two unrelated kindreds, and 9 were from patients with sporadic cases. All the patients had disease onset during early childhood. Of the patients with gigantism who did not carry an Xq26.3 microduplication, none presented before the age of 5 years. Genomic characterization of the Xq26.3 region suggests that the microduplications are generated during chromosome replication and that they contain four protein-coding genes. Only one of these genes, GPR101, which encodes a G-protein-coupled receptor, was overexpressed in patients' pituitary lesions. We identified a recurrent GPR101 mutation (p.E308D) in 11 of 248 patients with acromegaly, with the mutation found mostly in tumors. When the mutation was transfected into rat GH3 cells, it led to increased release of growth hormone and proliferation of growth hormone-producing cells.

CONCLUSIONS

We describe a pediatric disorder (which we have termed X-linked acrogigantism [X-LAG]) that is caused by an Xq26.3 genomic duplication and is characterized by early-onset gigantism resulting from an excess of growth hormone. Duplication of GPR101 probably causes X-LAG. We also found a recurrent mutation in GPR101 in some adults with acromegaly. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and others.).

Aryl hydrocarbon receptor-interacting protein gene mutations in familial isolated pituitary adenomas: analysis in 73 families

CONTEXT

An association between germline aryl hydrocarbon receptor-interacting protein (AIP) gene mutations and pituitary adenomas was recently shown.

OBJECTIVE

The objective of the study was to assess the frequency of AIP gene mutations in a large cohort of patients with familial isolated pituitary adenoma (FIPA).

DESIGN

This was a multicenter, international, collaborative study.

SETTING

The study was conducted in 34 university endocrinology and genetics departments in nine countries.

PATIENTS

Affected members from each FIPA family were studied. Relatives of patients with AIP mutations underwent AIP sequence analysis.

MAIN OUTCOME MEASURES

Presence/absence and description of AIP gene mutations were the main outcome measures.

INTERVENTION

There was no intervention.

RESULTS

Seventy-three FIPA families were identified, with 156 patients with pituitary adenomas; the FIPA cohort was evenly divided between families with homogeneous and heterogeneous tumor expression. Eleven FIPA families had 10 germline AIP mutations. Nine mutations, R16H, G47_R54del, Q142X, E174frameshift, Q217X, Q239X, K241E, R271W, and Q285frameshift, have not been described previously. Tumors were significantly larger (P = 0.0005) and diagnosed at a younger age (P = 0.0006) in AIP mutation-positive vs. mutation-negative subjects. Somatotropinomas predominated among FIPA families with AIP mutations, but mixed GH/prolactin-secreting tumors, prolactinomas, and nonsecreting adenomas were also noted. Approximately 85% of the FIPA cohort and 50% of those with familial somatotropinomas were negative for AIP mutations.

CONCLUSIONS

AIP mutations, of which nine new mutations have been described here, occur in approximately 15% of FIPA families. Although pituitary tumors occurring in association with AIP mutations are predominantly somatotropinomas, other tumor types are also seen. Further study of the impact of AIP mutations on protein expression and activity is necessary to elucidate their role in pituitary tumorigenesis in FIPA.

Clinical and genetic characterization of pituitary gigantism: an international collaborative study in 208 patients

Despite being a classical growth disorder, pituitary gigantism has not been studied previously in a standardized way. We performed a retrospective, multicenter, international study to characterize a large series of pituitary gigantism patients. We included 208 patients (163 males; 78.4%) with growth hormone excess and a current/previous abnormal growth velocity for age or final height >2 s.d. above country normal means. The median onset of rapid growth was 13 years and occurred significantly earlier in females than in males; pituitary adenomas were diagnosed earlier in females than males (15.8 vs 21.5 years respectively). Adenomas were ≥10 mm (i.e., macroadenomas) in 84%, of which extrasellar extension occurred in 77% and invasion in 54%. GH/IGF1 control was achieved in 39% during long-term follow-up. Final height was greater in younger onset patients, with larger tumors and higher GH levels. Later disease control was associated with a greater difference from mid-parental height (r=0.23, P=0.02). AIP mutations occurred in 29%; microduplication at Xq26.3 - X-linked acrogigantism (X-LAG) - occurred in two familial isolated pituitary adenoma kindreds and in ten sporadic patients. Tumor size was not different in X-LAG, AIP mutated and genetically negative patient groups. AIP-mutated and X-LAG patients were significantly younger at onset and diagnosis, but disease control was worse in genetically negative cases. Pituitary gigantism patients are characterized by male predominance and large tumors that are difficult to control. Treatment delay increases final height and symptom burden. AIP mutations and X-LAG explain many cases, but no genetic etiology is seen in >50% of cases.

Heterogeneous genetic background of the association of pheochromocytoma/paraganglioma and pituitary adenoma: results from a large patient cohort

CONTEXT

Pituitary adenomas and pheochromocytomas/paragangliomas (pheo/PGL) can occur in the same patient or in the same family. Coexistence of the two diseases could be due to either a common pathogenic mechanism or a coincidence.

OBJECTIVE

The objective of the investigation was to study the possible coexistence of pituitary adenoma and pheo/PGL.

DESIGN

Thirty-nine cases of sporadic or familial pheo/PGL and pituitary adenomas were investigated. Known pheo/PGL genes (SDHA-D, SDHAF2, RET, VHL, TMEM127, MAX, FH) and pituitary adenoma genes (MEN1, AIP, CDKN1B) were sequenced using next generation or Sanger sequencing. Loss of heterozygosity study and pathological studies were performed on the available tumor samples.

SETTING

The study was conducted at university hospitals.

PATIENTS

Thirty-nine patients with sporadic of familial pituitary adenoma and pheo/PGL participated in the study.

OUTCOME

Outcomes included genetic screening and clinical characteristics.

RESULTS

Eleven germline mutations (five SDHB, one SDHC, one SDHD, two VHL, and two MEN1) and four variants of unknown significance (two SDHA, one SDHB, and one SDHAF2) were identified in the studied genes in our patient cohort. Tumor tissue analysis identified LOH at the SDHB locus in three pituitary adenomas and loss of heterozygosity at the MEN1 locus in two pheochromocytomas. All the pituitary adenomas of patients affected by SDHX alterations have a unique histological feature not previously described in this context.

CONCLUSIONS

Mutations in the genes known to cause pheo/PGL can rarely be associated with pituitary adenomas, whereas mutation in a gene predisposing to pituitary adenomas (MEN1) can be associated with pheo/PGL. Our findings suggest that genetic testing should be considered in all patients or families with the constellation of pheo/PGL and a pituitary adenoma.

Genetic analysis in young patients with sporadic pituitary macroadenomas: besides AIP don't forget MEN1 genetic analysis

CONTEXT

Germline mutations in the aryl hydrocarbon receptor interacting protein gene (AIP) have been identified in young patients (age ≤30 years old) with sporadic pituitary macroadenomas. Otherwise, there are few data concerning the prevalence of multiple endocrine neoplasia type 1 (MEN1) mutations in such a population.

OBJECTIVE

We assessed the prevalence of both AIP and MEN1 genetic abnormalities (mutations and large gene deletions) in young patients (age ≤30 years old) diagnosed with sporadic and isolated macroadenoma, without hypercalcemia and/or MEN1-associated lesions.

DESIGN

The entire coding sequences of AIP and MEN1 were screened for mutations. In cases of negative sequencing screening, multiplex ligation-dependent probe amplification was performed for the detection of large genetic deletions.

PATIENTS AND SETTINGS

One hundred and seventy-four patients from endocrinology departments of 15 French University Hospital Centers were eligible for this study.

RESULTS

Twenty-one out of 174 (12%) patients had AIP (n=15, 8.6%) or MEN1 (n=6, 3.4%) mutations. In pediatric patients (age ≤18 years old), AIP/MEN1 mutation frequency reached nearly 22% (n=10/46). AIPmut and MEN1mut were identified in 8/79 (10.1%) and 1/79 (1.2%) somatotropinoma patients respectively; they each accounted for 4/74 (5.4%) prolactinoma (PRL) patients with mutations. Half of those patients (n=3/6) with gigantism displayed mutations in AIP. Interestingly, 4/12 (33%) patients with non-secreting adenomas bore either AIP or MEN1 mutations, whereas none of the eight corticotroph adenomas or the single thyrotropinoma case had mutations. No large gene deletions were observed in sequencing-negative patients.

CONCLUSION

Mutations in MEN1 can be of significance in young patients with sporadic isolated pituitary macroadenomas, particularly PRL, and together with AIP, we suggest genetic analysis of MEN1 in such a population.

High prevalence of AIP gene mutations following focused screening in young patients with sporadic pituitary macroadenomas

BACKGROUND

Aryl hydrocarbon receptor interacting protein (AIP) mutations (AIPmut) cause aggressive pituitary adenomas in young patients, usually in the setting of familial isolated pituitary adenomas. The prevalence of AIPmut among sporadic pituitary adenoma patients appears to be low; studies have not addressed prevalence in the most clinically relevant population. Hence, we undertook an international, multicenter, prospective genetic, and clinical analysis at 21 tertiary referral endocrine departments.

METHODS

We included 163 sporadic pituitary macroadenoma patients irrespective of clinical phenotype diagnosed at <30 years of age.

RESULTS

Overall, 19/163 (11.7%) patients had germline AIPmut; a further nine patients had sequence changes of uncertain significance or polymorphisms. AIPmut were identified in 8/39 (20.5%) pediatric patients. Ten AIPmut were identified in 11/83 (13.3%) sporadic somatotropinoma patients, in 7/61 (11.5%) prolactinoma patients, and in 1/16 non-functioning pituitary adenoma patients. Large genetic deletions were not seen using multiplex ligation-dependent probe amplification. Familial screening was possible in the relatives of seven patients with AIPmut and carriers were found in six of the seven families. In total, pituitary adenomas were diagnosed in 2/21 AIPmut-screened carriers; both had asymptomatic microadenomas.

CONCLUSION

Germline AIPmut occur in 11.7% of patients <30 years with sporadic pituitary macroadenomas and in 20.5% of pediatric patients. AIPmut mutation testing in this population should be considered in order to optimize clinical genetic investigation and management.

Mutations in the aryl hydrocarbon receptor interacting protein gene are not highly prevalent among subjects with sporadic pituitary adenomas

CONTEXT

Limited screening suggests that three germline mutations in the aryl hydrocarbon receptor interacting protein (AIP) gene are not involved in sporadic pituitary tumorigenesis. Multiple novel mutations of this gene have since been identified in familial isolated pituitary adenoma cohorts.

OBJECTIVE

The objective of the study was to undertake full AIP coding sequence screening to assess for the presence of germline and somatic mutations in European Union subjects with sporadic pituitary tumors.

DESIGN

The study design was the analysis of DNA from peripheral blood lymphocytes and analysis of exons 1-6 and paraexonic intron sequences of AIP. Multiplex ligation-dependent probe amplification was used to screen separate sporadic pituitary tumor tissue samples for discrete and extensive deletions or mutations of the AIP gene.

SETTING

The study was conducted in university tertiary referral Clinical Genetics, Molecular Biology, and Endocrinology Departments.

RESULTS

In 107 patients [prolactinomas (n =49), nonfunctioning tumors (n = 29), somatotropinomas (n = 26), ACTH-secreting tumors (n = 2), TSH-secreting tumors (n = 1)], no germline mutations of AIP were demonstrated. Among a group of 41 tumor samples from other subjects, a novel AIP mutation (R22X) was found in one sample in which the corresponding allele was deleted; follow-up screening of the patient demonstrated a germline R22X AIP mutation.

CONCLUSIONS

AIP mutations do not appear to play a prominent role in sporadic pituitary tumorigenesis in this population of European subjects.

Expression of aryl hydrocarbon receptor (AHR) and AHR-interacting protein in pituitary adenomas: pathological and clinical implications

Germline mutations of the aryl hydrocarbon receptor (AHR)-interacting protein (AIP) gene confer a predisposition to pituitary adenomas (PA), usually in the setting of familial isolated PA. To provide further insights into the possible role of AIP in pituitary tumour pathogenesis, the expression of AIP and AHR was determined by real-time RT-PCR and/or immunohistochemistry (IHC) in a large series of PA (n=103), including 17 with AIP mutations (AIP(mut)). Variable levels of AIP and AHR transcripts were detected in all PA, with a low AHR expression (P<0.0001 versus AIP). Cytoplasmic AIP and AHR were detected by IHC in 84.0 and 38.6% of PA respectively, and significantly correlated with each other (P=0.006). Nuclear AHR was detected in a minority of PA (19.7%). The highest AIP expression was observed in somatotrophinomas and non-secreting (NS) PA, and multivariate analysis in somatotrophinomas showed a significantly lower AIP immunostaining in invasive versus non-invasive cases (P=0.019). AIP expression was commonly low in other secreting PA. AIP immunostaining was abolished in a minority of AIP(mut) PA, with a frequent loss of cytoplasmic AHR and no evidence of nuclear AHR. In contrast, AIP overexpression in a subset of NS PA could be accompanied by nuclear AHR immunopositivity. We conclude that down-regulation of AIP and AHR may be involved in the aggressiveness of somatotrophinomas. Overall, IHC is a poorly sensitive tool for the screening of AIP mutations. Data obtained on AHR expression suggest that AHR signalling may be differentially affected according to PA phenotype.

Demonstration of enhanced potency of a chimeric somatostatin-dopamine molecule, BIM-23A387, in suppressing growth hormone and prolactin secretion from human pituitary somatotroph adenoma cells

In acromegaly, the combination of somatostatin (SS) and dopamine (DA) agonists has been shown to enhance suppression of GH secretion. In the present study, a new chimeric molecule, BIM-23A387, which selectively binds to the SS subtype 2 receptor (sst(2); K(i) = 0.10 nM) and to the DA D2 receptor (D2DR; K(i) = 22.1 nM) was tested in cultures prepared from 11 human GH-secreting tumors for its ability to suppress GH and prolactin (PRL) secretion. The chimeric compound was compared with individual sst(2) and D2DR agonists of comparable activity at the individual receptors. All tumors expressed both sst(2) and D2DR mRNAs (0.8 +/- 0.2 and 4.7 +/- 0.7 copy/copy beta-glucuronidase mRNA, respectively). In cell cultures from seven octreotide-sensitive tumors, the maximal inhibition of GH release induced by the individual sst(2) and D2DR analogs and by BIM-23A387 was similar. However, the mean EC(50) for GH suppression by BIM-23A387 (0.2 pM) was 50 times lower than that of the individual sst(2) and D2DR analogs, either used individually or combined. Similar data were obtained in four tumors that were only partially responsive to octreotide. The inhibition of GH release by BIM-23A387 was only partially reversed by the D2R2 antagonist, sulpiride, or by the sst(2) antagonist, BIM-23454. Only when both antagonists were combined was the GH suppressive effect of BIM-23A387 totally reversed. Finally, BIM-23A387 produced a mean 73 +/- 6% inhibition of PRL in six mixed GH plus PRL tumors. These data demonstrate an enhanced potency of the chimeric molecule, BIM-23A387, in suppressing GH and PRL secretion from acromegalic tumors, which cannot be explained merely on the basis of binding affinity for SS and/or DA receptors.

Congenital isolated adrenocorticotropin deficiency: an underestimated cause of neonatal death, explained by TPIT gene mutations

Tpit is a T box transcription factor important for terminal differentiation of pituitary proopiomelanocortin-expressing cells. We demonstrated that human and mouse mutations of the TPIT gene cause a neonatal-onset form of congenital isolated ACTH deficiency (IAD). In the absence of glucocorticoid replacement, IAD can lead to neonatal death by acute adrenal insufficiency. This clinical entity was not previously well characterized because of the small number of published cases. Since identification of the first TPIT mutations, we have enlarged our series of neonatal IAD patients to 27 patients from 21 unrelated families. We found TPIT mutations in 17 of 27 patients. We identified 10 different TPIT mutations, with one mutation found in five unrelated families. All patients appeared to be homozygous or compound heterozygous for TPIT mutations, and their unaffected parents are heterozygous carriers, confirming a recessive mode of transmission. We compared the clinical and biological phenotype of the 17 IAD patients carrying a TPIT mutation with the 10 IAD patients with normal TPIT-coding sequences. This series of neonatal IAD patients revealed a highly homogeneous clinical presentation, suggesting that this disease may be an underestimated cause of neonatal death. Identification of TPIT gene mutations as the principal molecular cause of neonatal IAD permits prenatal diagnosis for families at risk for the purpose of early glucocorticoid replacement therapy.

From pseudohypoparathyroidism to inactivating PTH/PTHrP signalling disorder (iPPSD), a novel classification proposed by the EuroPHP network

OBJECTIVE

Disorders caused by impairments in the parathyroid hormone (PTH) signalling pathway are historically classified under the term pseudohypoparathyroidism (PHP), which encompasses rare, related and highly heterogeneous diseases with demonstrated (epi)genetic causes. The actual classification is based on the presence or absence of specific clinical and biochemical signs together with an in vivo response to exogenous PTH and the results of an in vitro assay to measure Gsa protein activity. However, this classification disregards other related diseases such as acrodysostosis (ACRDYS) or progressive osseous heteroplasia (POH), as well as recent findings of clinical and genetic/epigenetic background of the different subtypes. Therefore, the EuroPHP network decided to develop a new classification that encompasses all disorders with impairments in PTH and/or PTHrP cAMP-mediated pathway.

DESIGN AND METHODS

Extensive review of the literature was performed. Several meetings were organised to discuss about a new, more effective and accurate way to describe disorders caused by abnormalities of the PTH/PTHrP signalling pathway.

RESULTS AND CONCLUSIONS

After determining the major and minor criteria to be considered for the diagnosis of these disorders, we proposed to group them under the term 'inactivating PTH/PTHrP signalling disorder' (iPPSD). This terminology: (i) defines the common mechanism responsible for all diseases; (ii) does not require a confirmed genetic defect; (iii) avoids ambiguous terms like 'pseudo' and (iv) eliminates the clinical or molecular overlap between diseases. We believe that the use of this nomenclature and classification will facilitate the development of rationale and comprehensive international guidelines for the diagnosis and treatment of iPPSDs.

Genetic screening of combined pituitary hormone deficiency: experience in 195 patients

CONTEXT

Mutations in transcription factors result in combined pituitary hormone deficiency (CPHD).

OBJECTIVE

A genetic screening strategy, based on endocrine and neuroradiological phenotype according to published knowledge, was applied to establish the prevalence of gene defects in each category of patients and provide a useful framework for clinicians to determine the genetic etiology and recurrence risks for individuals and families.

DESIGN

One hundred ninety-five CPHD patients from the international GENHYPOPIT network were studied, according to their phenotype, for POU1F1, PROP1, LHX3, LHX4, and HESX1.

PATIENTS

Patients selected had two pituitary hormone deficiencies or at least one deficiency with intracerebral malformations.

RESULTS

Total prevalence of mutations was 13.3 and 52.4% in 20 patients with familial CPHD history. No mutation of HESX1 was observed in 16 patients harboring septooptic dysplasia. A mutation of LHX4 gene, previously reported, was found in one familial case from 39 patients bearing pituitary stalk interruption syndrome. In 109 patients without extrapituitary abnormalities, 20 had PROP1 mutations, including eight patients with a family history of CPHD. Among 20 patients without pituitary stalk interruption syndrome, no LHX3 gene defect was found, even with a neck rotation deficit. One POU1F1 gene defect was found in one patient presenting the rare postpubertal association of thyrotroph (TSH deficiency) and somatotroph (GH deficiency) deficits.

CONCLUSIONS

Mutation of PROP1 gene remains the first to be looked for, and POU1F1 mutations should be sought in GH deficiency and TSH deficiency postpubertal population without extrapituitary malformations. Identification of gene defects allows early treatment of any deficit and prevention of their potentially fatal consequences. Genotyping appears highly beneficial at an individual and familial level.

Frequent large germline HRPT2 deletions in a French National cohort of patients with primary hyperparathyroidism

CONTEXT

Hyperparathyroidism-jaw tumor syndrome (HPT-JT) is an autosomal dominant syndrome with incomplete penetrance that can associate in a single patient parathyroid adenoma or carcinoma, fibro-osseous jaw tumor, cystic kidney lesion, and uterine tumor. Germline mutations of the HRPT2 gene (CDC73) coding for parafibromin are identified in approximately 50%-75% of HPT-JT cases and in approximately 14% of familial isolated hyperparathyroidism. A whole deletion of this gene has recently been reported in 1 sporadic case and in a family presenting with HPT-JT.

OBJECTIVE

The objective of the study was to report molecular abnormalities of the HRPT2 gene in patients with primary hyperparathyroidism in a French National cohort from the Groupe d'Étude des Tumeurs Endocrines.

METHODS

Patients' genomic DNA was screened by PCR-based sequencing for point mutations affecting HRPT2 and real-time quantitative PCR analysis for gross deletions.

RESULTS

We report 20 index patients with a germinal HRPT2 abnormality. Median age at diagnosis of primary hyperparathyroidism was 23 years (range 14-65 years). Median serum total calcium level at diagnosis was 3.19 mmol/L (range 2.8-4.3 mmol/L). Thirteen different mutations were identified by routine sequencing, including 7 mutations never reported. Seven patients (35%) carried a gross deletion of this gene (3 complete and 4 partial deletions). No genotype-phenotype correlation could be identified. A gross deletion of the HRPT2 gene was identified in 7% of patients for whom a routine screening by direct sequencing came up as negative.

CONCLUSION

Gross deletion analysis of the HRPT2 gene is indicated for all patients negative for mutation, presenting with HPT-JT or familial isolated hyperparathyroidism, parathyroid carcinoma, or in patients with apparently sporadic parathyroid adenoma diagnosed at a young age, having a severe hypercalcemia.

Everolimus and Octreotide for Patients with Recurrent Meningioma: Results from the Phase II CEVOREM Trial

PURPOSE

Aggressive meningiomas that progress after surgery/radiotherapy represent an unmet medical need. Strong and constant expression of SSTR2A receptors and activation of the Pi3K/Akt/mTOR pathway have been demonstrated in meningiomas. The combination of everolimus, an mTOR inhibitor, and octreotide, a somatostatin agonist, has shown additive antitumor effect in vitro. The phase II CEVOREM trial investigated the efficacy of this combination on recurrent meningiomas.

PATIENTS AND METHODS

Patients with documented recurrent tumor progression ineligible for further surgery/radiotherapy were eligible to receive octreotide (30 mg/d, day 1) and everolimus (10 mg/d, days 1-28). The primary endpoint was the 6-month progression-free survival rate (PFS6). The secondary endpoints were overall survival, response rate, tumor growth rate according to central review, and safety.

RESULTS

A total of 20 patients were enrolled, including 2 with World Health Organization (WHO) grade I tumors, 10 with WHO grade II tumors, and 8 with WHO grade III tumors; furthermore, 4 patients harbored NF2 germline mutation. The overall PFS6 was 55% [95% confidence interval (CI), 31.3%-73.5%], and overall 6- and 12-month survival rates were 90% (95% CI, 65.6%-97.4%) and 75% (95% CI, 50.0%-88.7%), respectively. A major decrease (>50%) was observed in the growth rate at 3 months in 78% of tumors. The median tumor growth rate decreased from 16.6%/3 months before inclusion to 0.02%/3 months at 3 months (P < 0.0002) and 0.48%/3 months at 6 months after treatment (P < 0.0003).

CONCLUSIONS

The combination of everolimus and octreotide was associated with clinical and radiological activity in aggressive meningiomas and warrants further studies. Decrease in the tumor volume growth rate should be considered a complementary and sensitive endpoint to select potentially effective drugs for recurrent meningiomas.

Prolactinomas resistant to bromocriptine: long-term efficacy of quinagolide and outcome of pregnancy

Resistance to bromocriptine, defined as the absence of normalization of prolactin (PRL) levels despite a 15-30 mg daily dose of bromocriptine during at least 6 months, has been observed in 5-17% of the prolactinomas according to the literature. The recent availability of a new potent dopamine agonist, quinagolide, prompted us to analyze its long-term therapeutic effects in 28 patients with prolactinomas resistant to bromocriptine. Before bromocriptine, their PRL levels were 520 +/- 185 micrograms/l (mean +/- SEM) and decreased to 291 +/- 154 micrograms/l after a 6-21 month period of bromocriptine treatment. All the women (N = 20) remained amenorrheic and hypogonadism was not improved in men (N = 8). Subsequently, after 1 year of 150-300 micrograms/day quinagolide, 12/28 patients of the present series recovered normal gonadal function and their initial mean baseline PRL value (404 +/- 180 micrograms/l) was 16 +/- 2 micrograms/l after 1 year of treatment. A significant tumor shrinkage was observed in 5/8 macroadenomas (62%). During the 3-year follow-up period under quinagolide, a similar good control was achieved in these patients, with the exception of one man presenting with a secondary rise of PRL under quinagolide. In contrast, 15 other patients (one patient interrupted quinagolide at 6 months because of poor tolerance) were not normalized under 150-450 micrograms/day quinagolide. Their initial PRL levels (606 +/- 298 micrograms/l) were reduced to 343 +/- 187 micrograms/l (versus 463 +/- 265 micrograms/l under bromocriptine after the same duration of treatment). Despite such a partial inhibitory effect of quinagolide, 7/12 women resumed menstrual cycles and three pregnancies occurred. In no case was any tumor shrinkage noticed during the 3-4-year follow-up. Three patients even presented, after 2 years of quinagolide treatment, with a secondary rise of PRL values associated with a further tumor growth in two patients. During the 3-year follow-up period, nine pregnancies occurred in seven women. In five women, after quinagolide withdrawal, the plasma PRL baseline values ranged from 52 to 158 micrograms/l and from 65 to 192 micrograms/l, respectively, at the first trimester and at the end of uneventful pregnancies. In contrast, in two women a rapid increase of PRL (240-400 micrograms/l) correlated with tumor growth during the first trimester. Such a tumor progression was blocked by quinagolide treatment but not by bromocriptine. These data, although observed in a limited series, justify the careful follow-up of pregnancies in this subclass of patients at risk. Finally, in the whole population, long-term control of hyperprolactinemia by quinagolide was obtained in 11/28 patients (39%) previously resistant to bromocriptine, and 15/20 women (75%) resumed normal gonadal function with a quinagolide daily dose of 300 micrograms in most of them.

The role of 18F-FDOPA and 18F-FDG-PET in the management of malignant and multifocal phaeochromocytomas

BACKGROUND

(18)F-DOPA has emerged as a promising tool in the localization of chromaffin-tissue-derived tumours. Interestingly, phaeochromocytomas (PHEO) are also FDG avid.

AIM AND METHODS

The aim of this study was to retrospectively evaluate the results of (18)F-FDOPA and/or (18)F-FDG-PET in patients with PHEO and paragangliomas (PGLs) and to compare the outcome of this approach with the traditional therapeutic work-up. Nine patients with non-MEN2 related PHEO or PGL were evaluated. At the time of the PET studies, the patients were classified into three groups based on their clinical history, conventional and SPECT imaging. The groups were malignant disease (n = 5, 1 VHL), apparently unique tumour site in patients with previous surgery (n = 1, SDHB) and multifocal tumours (n = 3, 1 VHL, 1 SDHD). (18)F-FDOPA and (18)F-FDG-PET PET/CT were then performed in all patients.

RESULTS

PET successfully identified additional tumour sites in five out of five patients with metastatic disease that had not been identified with SPECT + CI. Whilst tumour tracer uptake varied between patients it exhibited a consistently favourable residence time for delayed acquisitions. (18)F-FDOPA uptake (SUVmax) was superior to (18)F-FDG uptake in cases of neck PGL (three patients, four tumours). If only metastatic forms and abdominal PGLs were considered, (18)F-FDG provided additional information in three cases (two metastatic forms, one multifocal disease with SDHD mutation) compared to (18)F-FDOPA.

CONCLUSIONS

Our results suggest that tumour staging can be improved by combining (18)F-FDOPA and (18)F-FDG in the preoperative work-up of patients with abdominal and malignant PHEOs. (18)F-FDOPA is also an effective localization tool for neck PGLs. MIBG however, still has a role in these patients as MIBG and FDOPA images did not completely overlap.

The analysis of quantitative expression of somatostatin and dopamine receptors in gastro-entero-pancreatic tumours opens new therapeutic strategies

OBJECTIVE

Somatostatin (sst) are present in the majority of gastro-entero-pancreatic (GEP) tumours. Effects of somatostatin receptor (sst) analogues are partial and of limited duration. Cell lines derived from GEP express dopaminergic receptors D(2). New chimeric analogues simultaneously recognising sst(2) and sst(5) or sst(2) and D(2) have additive effects in inhibition of GH and prolactin secretion in pituitary adenomas. Our aim was to quantify the expression of sst and D(2) mRNA in human GEP tumours.

DESIGN AND METHODS

mRNA expression of sst(1), sst(2), sst(3) and sst(5) as well as D(2), was analysed using real-time PCR (TaqMan probe) in a series of 35 patients with GEP tumours (pancreas (n = 19) and intestinal (n = 16)). Levels of expression were compared with a group of 13 somatotroph adenomas.

RESULTS

All GEP tumours express sst(1), sst(2) and D(2). Expression of sst(3) and sst(5) was observed in 89 and 76% of tumours respectively with highly variable levels. sst(2) mRNA expression was higher in nonfunctional tumours (P < 0.009) and sst5 was higher in pancreatic than in intestinal tumours (P < 0.02). Whereas sst(2) levels were similar between GEP and somatotroph tumours, levels of sst(5) and D(2) were higher in the former (394.9 +/- 156.1 x 10(-2) vs 69.7 +/- 19.5 x 10(-2) copy/copy beta-Gus (P < 0.0036) and 519.6 +/- 121.2 x 10(-2) vs 50.0 +/- 21.6 x 10(-2) copy/copy beta-Gus (P < 0.0001) respectively). In small tumours ( < 30 mm), sst(2) density appeared as a crucial parameter in somatostatin receptor scintigraphy results, whereas in big tumours, a consistent bias in SRS results was introduced by the size. In pancreatic GEP, high-level sst(3) expression was found in tumours with more active angiogenesis (higher microvessel density and vascular endothelial growth factor expression (P < 0.03)).

CONCLUSIONS

GEP tumours co-express sst(2) and D(2) in 100% of cases and sst(5) in 89% thus supporting the testing of bi-specific agonists (sst(2)/sst(5) or sst(2)/D(2)) in these tumours.

A potential inhibitory role for the new truncated variant of somatostatin receptor 5, sst5TMD4, in pituitary adenomas poorly responsive to somatostatin analogs

CONTEXT

Somatostatin (SST) receptors, specially sst2 and sst5, provide a valuable target to inhibit excessive hormone release and cell growth in pituitary tumors by using SST analogs (SSAs). Unfortunately, an appreciable proportion of tumors fail to respond to SSA despite expressing high levels of one or more ssts. Recently we identified two novel truncated sst5 variants, sst5TMD5, and sst5TMD4, absent in normal pituitary but expressed in pituitary tumors.

OBJECTIVE AND DESIGN

We aimed at exploring the potential role of sst5TMD5 and sst5TMD4 in the poor response of some tumors to SSA in vivo and in vitro. Specifically, 25 somatotropinomas showing different responses to octreotide in vivo and sst2 (BIM-23197)- and sst5(BIM-23268)-selective compounds in vitro were screened for sst5TMD5/sst5TMD4 expression by real-time PCR. Relationships between ssts expression and in vivo and in vitro secretory response of the corresponding pituitary samples were assessed.

RESULTS

sst5TMD5 was absent in all samples analyzed. sst5TMD4 was found in 85% of tumors, and its expression was positively correlated to that of sst5 (R(2) = 0.79, P < 0.001). Expression of sst5TMD4 was negatively correlated with the ability of octreotide to reduce GH levels in vivo and partially negatively correlated with inhibition of GH secretion by an sst5 selective agonist (BIM-23268) in vitro.

CONCLUSIONS

These results indicate that sst5TMD4 is related to the reduced ability of octreotide at normalizing hormone secretion in poorly responsive tumors in vivo. Further studies will help to evaluate the potential use of sst5TMD4 expression in surgically removed pituitary adenomas as a predictor of the subsequent response of different pituitary tumors to SSA therapy.

A genome-wide approach reveals novel imprinted genes expressed in the human placenta

Genomic imprinting characterizes genes with a monoallelic expression, which is dependent on the parental origin of each allele. Approximately 150 imprinted genes are known to date, in humans and mice but, though computational searches have tried to extract intrinsic characteristics of these genes to identify new ones, the existing list is probably far from being comprehensive. We used a high-throughput strategy by diverting the classical use of genotyping microarrays to compare the genotypes of mRNA/cDNA vs. genomic DNA to identify new genes presenting monoallelic expression, starting from human placental material. After filtering of data, we obtained a list of 1,082 putative candidate monoallelic SNPs located in more than one hundred candidate genes. Among these, we found known imprinted genes, such as IPW, GRB10, INPP5F and ZNF597, which contribute to validate the approach. We also explored some likely candidates of our list and identified seven new imprinted genes, including ZFAT, ZFAT-AS1, GLIS3, NTM, MAGI2, ZC3H12Cand LIN28B, four of which encode zinc finger transcription factors. They are, however, not imprinted in the mouse placenta, except for Magi2. We analyzed in more details the ZFAT gene, which is paternally expressed in the placenta (as ZFAT-AS1, a non-coding antisense RNA) but biallelic in other tissues. The ZFAT protein is expressed in endothelial cells, as well as in syncytiotrophoblasts. The expression of this gene is, moreover, downregulated in placentas from complicated pregnancies. With this work we increase by about 10% the number of known imprinted genes in humans.

Pituitary stalk interruption syndrome in 83 patients: novel HESX1 mutation and severe hormonal prognosis in malformative forms

BACKGROUND

Pituitary stalk interruption syndrome (PSIS) is a particular entity in the population of patients with hypopituitarism. Only rare cases have a known genetic cause.

OBJECTIVES

i) To compare subgroups with or without extra-pituitary malformations (EPM) in a cohort of PSIS patients to identify predictive factors of evolution, ii) to determine the incidence of mutations of the known pituitary transcription factor genes in PSIS. Study design We analyzed features of 83 PSIS patients from 80 pedigrees and screened HESX1, LHX4, OTX2, and SOX3 genes.

RESULTS

PSIS had a male predominance and was rarely familial (5%). Pituitary hypoplasia was observed only in the group with EPM. Multiple hormone deficits were observed significantly more often with versus without EPM (87.5 vs 69.5% respectively). Posterior pituitary location along the stalk was a significant protective factor regarding severity of hormonal phenotype. A novel HESX1 causative mutation was found in a consanguineous family, and two LHX4 mutations were present in familial PSIS.

CONCLUSION

PSIS patients with EPM had a more severe hormonal disorder and pituitary imaging status, suggesting an antenatal origin. HESX1 or LHX4 mutations accounted for <5% of cases and were found in consanguineous or familial cases.