Characterization of neuroendocrine tumors in heterozygous mutant MENX rats: a novel model of invasive medullary thyroid carcinoma.

Rats affected by the MENX syndrome spontaneously develop multiple neuroendocrine tumors (NETs) including adrenal, pituitary and thyroid gland neoplasms. MENX was initially reported to be inherited as a recessive trait and affected rats were found to be homozygous for the predisposing mutation encoding p27. We here report that heterozygous MENX-mutant rats (p27+/mut) develop the same spectrum of NETs seen in the homozygous (p27mut/mut) animals but with slower progression.

uPAR enhances malignant potential of triple-negative breast cancer by directly interacting with uPA and IGF1R.

Background: Due to lack of a targeted therapy for the triple-negative breast cancer (TNBC) patients, it is important to explore this aggressive breast cancer type in more detail and to establish novel therapeutic approaches. TNBC is defined negative for the protein expression of oestrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2). One prominent feature of this cancer type is the frequent overexpression of major components of the urokinase-type plasminogen activator system (uPAS) including uPA, its receptor uPAR and the inhibitor PAI-1, which may be valuable as therapeutic targets.

Association between the p27 rs2066827 variant and tumor multiplicity in patients harboring MEN1 germline mutations.

Objective: To date, no evidence of robust genotype-phenotype correlation or disease modifiers for multiple endocrine neoplasia type 1 (MEN1) syndrome has been described, leaving the highly variable clinical presentation of patients unaccounted for.

Design: As the CDKN1B (p27) gene causes MEN4 syndrome and it is transcriptionally regulated by the product of the MEN1 gene (menin), we sought to analyze whether p27 influences the phenotype of MEN1-mutated patients. The cohort consisted of 100 patients carrying germline MEN1 gene mutations and 855 population-matched control individuals.

p27 variant and corticotropinoma susceptibility: a genetic and in vitro study.

Germline mutations in p27(kip1) are associated with increased susceptibility to multiple endocrine neoplasias (MEN) both in rats and humans; however, the potential role of common polymorphisms of this gene in endocrine tumor susceptibility and tumorigenesis remains mostly unrecognized. To assess the risk associated with polymorphism rs2066827 (p27-V109G), we genotyped a large cohort of Brazilian patients with sporadic endocrine tumors (pituitary adenomas, n=252; pheochromocytomas, n=125; medullary thyroid carcinoma, n=51; and parathyroid adenomas, n=19) and 885 population-matched healthy controls and determined the odds ratios and 95% CIs. Significant associations were found for the group of patients with pituitary adenomas (P=0.

Understanding the role of the Q338H MUTYH variant in oxidative damage repair.

The MUTYH DNA-glycosylase is indirectly engaged in the repair of the miscoding 7,8-dihydro-8-oxo-2'-deoxyguanine (8-oxodG) lesion by removing adenine erroneously incorporated opposite the oxidized purine. Inherited biallelic mutations in the MUTYH gene are responsible for a recessive syndrome, the MUTYH-associated polyposis (MAP), which confers an increased risk of colorectal cancer. In this study, we functionally characterized the Q338H variant using recombinant proteins, as well as cell-based assays.

Functional Imaging of Pheochromocytoma with Ga-DOTATOC and C-HED in a Genetically Defined Rat Model of Multiple Endocrine Neoplasia.

Rats affected by the MENX multitumor syndrome develop pheochromocytoma (100%). Pheochromocytomas are uncommon tumors and animal models are scarce, hence the interest in MENX rats to identify and preclinically evaluate novel targeted therapies. A prerequisite for such studies is a sensitive and noninvasive detection of MENXassociated pheochromocytoma.

Somatic mutation and germline sequence abnormalities in CDKN1B, encoding p27Kip1, in sporadic parathyroid adenomas.

Context: Typical nonfamilial (sporadic) parathyroid adenomas are common endocrine tumors for which no predisposing germline DNA variants and only a few clonally altered genes that drive parathyroid tumorigenesis have been identified. CDKN1B, encoding cyclin-dependent kinase inhibitor p27(kip1), has recently been implicated in a multiple endocrine tumor phenotype in rats and, rarely, in a human familial MEN1 (multiple endocrine neoplasia type 1)-like disorder.

Objective: We sought to determine whether mutation of CDKN1B might contribute to the development of common sporadic parathyroid adenomas.

Pheochromocytoma in rats with multiple endocrine neoplasia (MENX) shares gene expression patterns with human pheochromocytoma.

Pheochromocytomas are rare neoplasias of neural crest origin arising from chromaffin cells of the adrenal medulla and sympathetic ganglia (extra-adrenal pheochromocytoma). Pheochromocytoma that develop in rats homozygous for a loss-of-function mutation in p27Kip1 (MENX syndrome) show a clear progression from hyperplasia to tumor, offering the possibility to gain insight into tumor pathobiology. We compared the gene-expression signatures of both adrenomedullary hyperplasia and pheochromocytoma with normal rat adrenal medulla.

A novel germline CDKN1B mutation causing multiple endocrine tumors: clinical, genetic and functional characterization.

Multiple endocrine neoplasia (MEN) syndromes are characterized by tumors involving two or more endocrine glands. Two MEN syndromes have long been known: MEN1 and MEN2,caused by germline mutations in MEN1 or RET, respectively. Recently, mutations in CDKN1B,encoding the cyclin-dependent kinase (Cdk) inhibitor p27, were identified in patients having a MEN1-like phenotype but no MEN1 gene mutations.

The MENX syndrome and p27: relationships with multiple endocrine neoplasia.

In the past 3 years new insight into the etiopathogenesis of hereditary endocrine tumors has emerged from studies conducted on MENX, a rat multiple endocrine neoplasia (MEN) syndrome. MENX spontaneously developed in a rat colony and was discovered by serendipity when these animals underwent complete necropsy, as they were found to consistently develop multiple endocrine tumors with a spectrum similar to both MEN type 1 (MEN1) and MEN2 human syndromes. Genetic studies identified a germline mutation in the Cdkn1b gene, encoding the p27 cell cycle inhibitor, as the causative mutation for the MENX syndrome.

Characterization of a naturally-occurring p27 mutation predisposing to multiple endocrine tumors.

Background: p27Kip1 (p27) is an important negative regulator of the cell cycle and a putative tumor suppressor. The finding that a spontaneous germline frameshift mutation in Cdkn1b (encoding p27) causes the MENX multiple endocrine neoplasia syndrome in the rat provided the first evidence that Cdkn1b is a tumor susceptibility gene for endocrine tumors. Noteworthy, germline p27 mutations were also identified in human patients presenting with endocrine tumors.

MUTYH mutations associated with familial adenomatous polyposis: functional characterization by a mammalian cell-based assay.

MUTYH-associated polyposis (MAP) is a colorectal cancer syndrome, due to biallelic mutations of MUTYH. This Base Excision Repair gene encodes for a DNA glycosylase that specifically mitigates the high mutagenic potential of the 8-hydroxyguanine (8-oxodG) along the DNA. Aim of this study was to characterize the biological effects, in a mammalian cell background, of human MUTYH mutations identified in MAP patients (137insIW [c.

Role of MUTYH and MSH2 in the control of oxidative DNA damage, genetic instability, and tumorigenesis.

Mismatch repair is the major pathway controlling genetic stability by removing mispairs caused by faulty replication and/or mismatches containing oxidized bases. Thus, inactivation of the Msh2 mismatch repair gene is associated with a mutator phenotype and increased cancer susceptibility. The base excision repair gene Mutyh is also involved in the maintenance of genomic integrity by repairing premutagenic lesions induced by oxidative DNA damage.

Functional analysis and case-control study of -160C/A polymorphism in the E-cadherin gene promoter: association with cancer risk.

Background: A C-->A polymorphism within the CDH1 (E-cadherin) promoter seems to be associated with a reduced efficiency of gene transcription in vitro. Due to the crucial role of E-cadherin in epithelia, tissue-specific effect of C-->A change on CDH1 transcription was tested and a case-control study was performed on patients affected with epithelial tumors.

Patients And Methods: The -178/+93 CDH1 region containing either C or A nucleotide was inserted upstream of the Luciferase reporter gene in the pGL-2 vector, and the construct activity was assessed by transient transfection assay in HeLa and HCT116 cells.

Constitutional high expression of an APC mRNA isoform in a subset of attenuated familial adenomatous polyposis patients.

Familial adenomatous polyposis is an inherited condition associated with hundreds to thousands of colorectal adenomas conferring a very high risk of cancer at a young age. In addition to "classical" form, there is also an attenuated polyposis, with fewer than 100 polyps and a delayed age of cancer onset. Both classical and attenuated polyposis are characterized by a relevant phenotypic heterogeneity.

High frequency of MYH gene mutations in a subset of patients with familial adenomatous polyposis.

Background & Aims: Inherited colorectal polyposis has been linked to constitutive mutations of the APC tumor suppressor gene. Recently, germline mutations in the base excision repair gene MYH have been associated with a recessively inherited form of the disease. The aim of this study was to evaluate germline mutation frequencies of both MYH and APC susceptibility genes in Italian patients with attenuated familial adenomatous polyposis.