Genetic Factors in the Development of Pituitary Adenomas.
; ; et al
in Endocrine Development (2010), 17
Pituitary adenomas are one of the most frequent intracranial tumors. Usually, they are benign but are of great clinical significance because of tumor compression syndrome and hormone overproduction. The ... [more ▼]
Pituitary adenomas are one of the most frequent intracranial tumors. Usually, they are benign but are of great clinical significance because of tumor compression syndrome and hormone overproduction. The interest in this pathology is increasing, particularly after some recent reports on their prevalence that proved to be 3-5 times more than previously estimated. Pituitary tumors arise in a sporadic setting and rarely as part of hereditary genetic syndromes. Such rare hereditary conditions like MEN1, Carney complex and McCune-Albright syndrome give significant insight into pituitary tumorigenesis. Newer genes associated pituitary tumor development include CDKN1B (MEN4) and AIP, the latter of which is involved in the pathophysiology of 15% of FIPA kindreds. The number of genes involved in pituitary tumorigenesis is progressively increasing and the possible mechanisms of action include signal transduction pathways, cell cycle regulators, growth factors, chromosome instability and others. Nevertheless, in the majority of sporadic adenomas, the primary genetic defect remains unknown. Furthermore, there is not a well established relationship between the genotype and its influence on the protein expression, ligand-receptor interaction, tumor growth or hormone hyperproduction. Further studies should evaluate the clinical significance of genetic alterations and their implications for existing and new therapeutic options. [less ▲]Detailed reference viewed: 18 (10 ULg)
Aggressive pituitary adenomas occurring in young patients in a large Polynesian kindred with a germline R271W mutation in the AIP gene.
; ; et al
in European Journal of Endocrinology (2009), 161(5), 799-804
OBJECTIVE: Mutations in the aryl hydrocarbon receptor-interacting protein (AIP) were recently shown to confer a pituitary adenoma predisposition in patients with familial isolated pituitary adenomas (FIPA ... [more ▼]
OBJECTIVE: Mutations in the aryl hydrocarbon receptor-interacting protein (AIP) were recently shown to confer a pituitary adenoma predisposition in patients with familial isolated pituitary adenomas (FIPA). We report a large Samoan FIPA kindred from Australia/New Zealand with an R271W mutation that was associated with aggressive pituitary tumors. DESIGN AND METHODS: Case series with germline screening of AIP and haplotype analyses among R271W families. RESULTS: This previously unreported kindred consisted of three affected individuals that either presented with or had first symptoms of a pituitary macroadenoma in late childhood or adolescence. The index case, a 15-year-old male with incipient gigantism and his maternal aunt, had somatotropinomas, and the maternal uncle of the index case had a prolactinoma. All tumors were large (15, 40, and 60 mm maximum diameter) and two required transcranial surgery and radiotherapy. All three affected subjects and ten other unaffected relatives were found to be positive for a germline R271W AIP mutation. Comparison of the single nucleotide polymorphism patterns among this family and two previously reported European FIPA families with the same R271W mutation demonstrated no common ancestry. CONCLUSIONS: This kindred exemplifies the aggressive features of pituitary adenomas associated with AIP mutations, while genetic analyses among three R271W FIPA families indicate that R271W represents a mutational hotspot that should be studied further in functional studies. [less ▲]Detailed reference viewed: 20 (5 ULg)
Tumor ZAC1 expression is associated with the response to somatostatin analog therapy in patients with acromegaly.
; ; et al
in International Journal of Cancer = Journal International du Cancer (2009), 125(9), 2122-6
Somatostatin analogs (SSA) with their potent antisecretory and antiproliferative effects are the main medical treatment option for patients with neuroendocrine tumors, such as gastroenteropancreatic and ... [more ▼]
Somatostatin analogs (SSA) with their potent antisecretory and antiproliferative effects are the main medical treatment option for patients with neuroendocrine tumors, such as gastroenteropancreatic and acromegaly-associated growth hormone secreting pituitary tumors. Although a good portion of acromegalic patients gets normalized after SSA treatment, strict hormonal control is not achieved in a sizeable proportion of these patients. The reasons for this incomplete response to SSA treatment are unclear. We have found that the tumor suppressor ZAC1 (LOT1/PLAGL1) is essential for the antiproliferative effect of SSA in pituitary tumor cells. The aim of the present retrospective cohort study was to determine whether ZAC1 immunoreactivity in archival somatotrophinoma tissue derived from 45 patients with acromegaly routinely pretreated with SSA before surgery, was associated with response to SSA (normalization of GH, IGF-I and presence of tumor shrinkage). All tumors displayed ZAC1 immunoreactivity [weak (+; n = 15), moderate (++; n = 16) and strong (+++; n = 14)]. A significant positive correlation was found between strong ZAC1 immunoreactivity and IGF-I normalization and presence of tumor shrinkage after SSA treatment, which was not affected by age at diagnosis, gender or duration of SSA treatment. These in vivo data combined with the antiproliferative properties of ZAC1/Zac1 provide evidence of a mechanistic role for this transcription factor on SSA induced tumor shrinkage and hormone normalization. [less ▲]Detailed reference viewed: 24 (8 ULg)
De la Génétique des adénomes hypophysaires familiaux
Scientific conference (2009, October 27)Detailed reference viewed: 6 (0 ULg)
De la génétique des adénomes hypophysaires familiaux
Beckers, Albert ; ; Daly, Adrian
in Bulletin de l'Académie Nationale de Médecine (2009), 193(7), 1557-1571
Pituitary adenomas were previously thought to be rare. However, a recent cross-sectional study conducted in Liège, Belgium, showed that clinically apparent pituitary adenomas were present in about 1 in ... [more ▼]
Pituitary adenomas were previously thought to be rare. However, a recent cross-sectional study conducted in Liège, Belgium, showed that clinically apparent pituitary adenomas were present in about 1 in 1000 inhabitants, which is 4 to 5 times the previously reported prevalence. Pituitary adenomas are generally sporadic, but some are associated with familial-isolated tumoral syndromes (mainly MEN1 and Carney complex). With the recent characterization of FIPA (Familial Isolated Pituitary Adenomas), familial pituitaru adenomas are now thought to account for 5 % to 8 % of all pituitary tumors. New genetic mechanisms are being identified, improving our understanding of the complex manifestations and sometimes unpredictable outcome of pituitary adenomas. [less ▲]Detailed reference viewed: 53 (5 ULg)
Le Secret des Géants : Une aventure d'épidémiologie médicale
Scientific conference (2009, October 23)Detailed reference viewed: 8 (1 ULg)
Caractéristiques cliniques et génétiques des "Familial Isolated Pituitary Adenomas"
Scientific conference (2009, October 10)Detailed reference viewed: 5 (0 ULg)
The epidemiology and genetics of pituitary adenomas.
Daly, Adrian ; ; Beckers, Albert
in Best Practice & Research. Clinical Endocrinology & Metabolism (2009), 23(5), 543-554
According to data derived from autopsy and radiological imaging series, pituitary tumours occur very commonly in the general population; however, most of these tumours are incidental findings with no ... [more ▼]
According to data derived from autopsy and radiological imaging series, pituitary tumours occur very commonly in the general population; however, most of these tumours are incidental findings with no obvious clinical impact. The historical data on the prevalence of pituitary adenomas in the clinical setting are scant and point to such tumours being relatively rare. Recent studies have shown that the prevalence of clinically relevant pituitary adenomas is 3-5 times higher than previously reported, which adds impetus to research into the aetiology of these tumours. Although the majority of pituitary adenomas are sporadic, approximately 5% of all cases occur in a familial setting and over half of these are due to Multiple Endocrine Neoplasia Type 1 (MEN-1) and Carney's Complex (CNC) disorders. Since the late 1990 s, we have described non-MEN1/CNC familial pituitary tumours that include all tumour phenotypes as a condition termed Familial Isolated Pituitary Adenomas (FIPAs). The clinical characteristics of the FIPAs vary from those sporadic pituitary adenomas, as patients with FIPAs have a younger age at diagnosis and larger tumours. About 15% of the FIPA patients have mutations in the aryl hydrocarbon receptor-interacting protein gene (AIP), which indicates that the FIPA may have a diverse genetic pathophysiology. [less ▲]Detailed reference viewed: 31 (4 ULg)
Epidémiologie et génétique des adénomes hypophysaires
Scientific conference (2009, September 24)Detailed reference viewed: 7 (0 ULg)
Expression of aryl hydrocarbon receptor (AHR) and AHR-interacting protein in pituitary adenomas: pathological and clinical implications.
; ; et al
in Endocrine-Related Cancer (2009), 16(3), 1029-1043
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 ... [more ▼]
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. [less ▲]Detailed reference viewed: 36 (9 ULg)
Mutaciones de AIP en adenomas hipofisarios familiares y esporadicos: experiencia local y revision de la literatura.
; Daly, Adrian ; et al
in Endocrinologia y Nutricion (2009), 56(7), 369-377
Clinically relevant pituitary adenomas occur 3-5 times more frequently than previously thought. The majority are isolated cases, but their presentation can be familial in the setting of known syndromes ... [more ▼]
Clinically relevant pituitary adenomas occur 3-5 times more frequently than previously thought. The majority are isolated cases, but their presentation can be familial in the setting of known syndromes such as multiple endocrine neoplasia (MEN)-1 and Carney complex. When 2 or more cases of pituitary adenomas occur in the same family in the absence of the above-mentioned syndromes, a diagnosis of FIPA (familial isolated pituitary adenomas) is made, which accounts for 1-2% of all pituitary adenomas. Mutations of the gene AIP (aryl hydrocarbon receptor-interacting protein) may account for 15% of FIPA families (50% of familial acromegaly), and as such the genetic causes continue to be studied. Also mutations in AIP can be detected in sporadic adenomas among young populations (< 30 years of age). We describe the characteristics of FIPA, detailing the study of a spanish family, in this case AIP mutation negative. Also, the reported findings in sporadic adenomas in the young population are detailed, accompanied by the description of a 19- year old patient with an intronic AIP mutation. Multicenter studies have provided understanding of aspects such as mutations in AIP; however, further studies are necessary to identify other genes involved in FIPA and sporadic pituitary adenomas occurring at a young age. [less ▲]Detailed reference viewed: 33 (2 ULg)