Browsing by Author "Grossman, Ashley B. (35401342800)"

Objective: Germline mutations in the MEN1 gene predispose to the multiple endocrine neoplasia (MEN1) syndrome; however, approximately 10-20% of patients with MEN1 do not have a detectable MEN1 mutation. A rat strain with multiple endocrine tumours, a phenotypic overlap of both MEN1 and MEN2, has been reported to have a homozygous germline p27 (CDKN1B) mutation. Recently, two MEN1 mutation-negative MEN1 syndrome patients have been identified to harbour a germline CDKN1B mutation. The recently identified gene AIP can also cause familial isolated pituitary adenoma, but no other specific tumour is associated with this syndrome. The objective of this study was to evaluate the possible contribution of CDKN1B and AIP germline mutations in a cohort of MEN1 mutation-negative MEN1 syndrome patients. Patients: Eighteen sporadic and three familial cases of MEN1 mutation-negative MEN1 syndrome were studied (18 pituitary adenomas, 12 hyperparathyroidism, 10 neuroendocrine tumours including 2 ACTH-secreting lesions and one adrenal nodular hyperplasia). Clinical data and genomic DNA were analysed for mutations in the CDKN1B and AIP genes. Results: There were no mutations in the coding region or exon/intron junction of the CDKN1B and AIP genes in any patient. Although we have a limited number of patients in our cohort, our data is consistent with others in the literature suggesting that CDKN1B and AIP mutations are extremely rare in MEN1 syndrome. Conclusion: Our results suggest that mutations in the CDKN1B and AIP genes are relatively uncommon in MEN1 mutation-negative MEN1 syndrome patients. © 2009 The Authors.

Objective: Germline mutations in the MEN1 gene predispose to the multiple endocrine neoplasia (MEN1) syndrome; however, approximately 10-20% of patients with MEN1 do not have a detectable MEN1 mutation. A rat strain with multiple endocrine tumours, a phenotypic overlap of both MEN1 and MEN2, has been reported to have a homozygous germline p27 (CDKN1B) mutation. Recently, two MEN1 mutation-negative MEN1 syndrome patients have been identified to harbour a germline CDKN1B mutation. The recently identified gene AIP can also cause familial isolated pituitary adenoma, but no other specific tumour is associated with this syndrome. The objective of this study was to evaluate the possible contribution of CDKN1B and AIP germline mutations in a cohort of MEN1 mutation-negative MEN1 syndrome patients. Patients: Eighteen sporadic and three familial cases of MEN1 mutation-negative MEN1 syndrome were studied (18 pituitary adenomas, 12 hyperparathyroidism, 10 neuroendocrine tumours including 2 ACTH-secreting lesions and one adrenal nodular hyperplasia). Clinical data and genomic DNA were analysed for mutations in the CDKN1B and AIP genes. Results: There were no mutations in the coding region or exon/intron junction of the CDKN1B and AIP genes in any patient. Although we have a limited number of patients in our cohort, our data is consistent with others in the literature suggesting that CDKN1B and AIP mutations are extremely rare in MEN1 syndrome. Conclusion: Our results suggest that mutations in the CDKN1B and AIP genes are relatively uncommon in MEN1 mutation-negative MEN1 syndrome patients. © 2009 The Authors.

Abnormal microRNA (miRNA) expression profiles have recently been associated with sporadic pituitary adenomas, suggesting that miRNAs can contribute to tumor formation; miRNAs are small noncoding RNAs that inhibit posttranscriptional expression of target mRNAs by binding to target sequences usually located in the 3'-UTR. In this study, we investigated the role played by miR-107, a miRNA associated with different human cancers, in sporadic pituitary adenomas and its interaction with the pituitary tumor suppressor gene aryl hydrocarbon receptor-interacting protein (AIP). miR-107 expression was evaluated in pituitary adenoma and normal pituitary samples using microRNA screen TLDA (TaqMan Low-Density Array) and RT-qPCR assays. We show that miR-107 expression was significantly upregulated in GH-secreting and nonfunctioning pituitary adenomas. We found that human AIP-3'-UTR is a target of miR-107 since miR-107 inhibited in vitro AIP expression to 53.9 + 2% of the miRNA control in a luciferase assay and reduced endogenous AIP mRNA expression to 53 + 22% of the miRNA control in human cells. However, we did not observe a negative correlation between AIP and miR-107 expression in the human tumor samples. Furthermore, we show that miR-107 overexpression inhibited cell proliferation in human neuroblastoma and rat pituitary adenoma cells. In conclusion, miR-107 is overexpressed in pituitary adenomas and may act as a tumor suppressor. We have identified and confirmed AIP as a miR-107 target gene. Expression data in human samples suggest that the expression of AIP and miR-107 could be influenced by a combination of tumorigenic factors as well as compensatory mechanisms stimulated by the tumorigenic process. © 2012 the American Physiological Society.

Objective: Heterozygous germline loss-of-function variants in AIP are associated with young-onset growth hormone and/or prolactin-secreting pituitary tumours. However, the pathogenic role of the c.911G > A; p.(Arg304Gln) (R304Q) AIP variant has been controversial. Recent data from public exome/genome databases show this variant is not infrequent. The objective of this work was to reassess the pathogenicity of R304Q based on clinical, genomic, and functional assay data. Design: Data were collected on published R304Q pituitary neuroendocrine tumour cases and from International Familial Isolated Pituitary Adenoma Consortium R304Q cases (n = 38, R304Q cohort). Clinical features, population cohort frequency, computational analyses, prediction models, presence of loss-of-heterozygosity, and in vitro/in vivo functional studies were assessed and compared with data from pathogenic/likely pathogenic AIP variant patients (AIPmut cohort, n = 184). Results: Of 38 R304Q patients, 61% (23/38) had growth hormone excess, in contrast to 80% of AIPmut cohort (147/184, P < .001). R304Q cohort was older at disease onset and diagnosis than the AIPmut cohort (median [quartiles] onset: 25 y [16-35] vs 16 y [14-23], P < .001; median [quartiles] diagnosis: 36 y [24-44] vs 21 y [15-29], P < .001). R304Q is present in gnomADv2.1 (0.31%) and UK Biobank (0.16%), including three persons with homozygous R304Q. No loss-of-heterozygosity was detected in four R304Q pituitary neuroendocrine tumour samples. In silico predictions and experimental data were conflicting. Conclusions: Evidence suggests that R304Q is not pathogenic for pituitary neuroendocrine tumour. We recommend changing this variant classification to likely benign and do not recommend pre-symptomatic genetic testing of family members or follow-up of already identified unaffected individuals with the R304Q variant. © The Author(s) 2025. Published by Oxford University Press on behalf of European Society of Endocrinology.

Objective: Heterozygous germline loss-of-function variants in AIP are associated with young-onset growth hormone and/or prolactin-secreting pituitary tumours. However, the pathogenic role of the c.911G > A; p.(Arg304Gln) (R304Q) AIP variant has been controversial. Recent data from public exome/genome databases show this variant is not infrequent. The objective of this work was to reassess the pathogenicity of R304Q based on clinical, genomic, and functional assay data. Design: Data were collected on published R304Q pituitary neuroendocrine tumour cases and from International Familial Isolated Pituitary Adenoma Consortium R304Q cases (n = 38, R304Q cohort). Clinical features, population cohort frequency, computational analyses, prediction models, presence of loss-of-heterozygosity, and in vitro/in vivo functional studies were assessed and compared with data from pathogenic/likely pathogenic AIP variant patients (AIPmut cohort, n = 184). Results: Of 38 R304Q patients, 61% (23/38) had growth hormone excess, in contrast to 80% of AIPmut cohort (147/184, P < .001). R304Q cohort was older at disease onset and diagnosis than the AIPmut cohort (median [quartiles] onset: 25 y [16-35] vs 16 y [14-23], P < .001; median [quartiles] diagnosis: 36 y [24-44] vs 21 y [15-29], P < .001). R304Q is present in gnomADv2.1 (0.31%) and UK Biobank (0.16%), including three persons with homozygous R304Q. No loss-of-heterozygosity was detected in four R304Q pituitary neuroendocrine tumour samples. In silico predictions and experimental data were conflicting. Conclusions: Evidence suggests that R304Q is not pathogenic for pituitary neuroendocrine tumour. We recommend changing this variant classification to likely benign and do not recommend pre-symptomatic genetic testing of family members or follow-up of already identified unaffected individuals with the R304Q variant. © The Author(s) 2025. Published by Oxford University Press on behalf of European Society of Endocrinology.