976 resultados para FREQUENCIES


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Genotype-environment interactions (GEI) limit genetic gain for complex traits such as tolerance to drought. Characterization of the crop environment is an important step in understanding GEI. A modelling approach is proposed here to characterize broadly (large geographic area, long-term period) and locally (field experiment) drought-related environmental stresses, which enables breeders to analyse their experimental trials with regard to the broad population of environments that they target. Water-deficit patterns experienced by wheat crops were determined for drought-prone north-eastern Australia, using the APSIM crop model to account for the interactions of crops with their environment (e.g. feedback of plant growth on water depletion). Simulations based on more than 100 years of historical climate data were conducted for representative locations, soils, and management systems, for a check cultivar, Hartog. The three main environment types identified differed in their patterns of simulated water stress around flowering and during grain-filling. Over the entire region, the terminal drought-stress pattern was most common (50% of production environments) followed by a flowering stress (24%), although the frequencies of occurrence of the three types varied greatly across regions, years, and management. This environment classification was applied to 16 trials relevant to late stages testing of a breeding programme. The incorporation of the independently-determined environment types in a statistical analysis assisted interpretation of the GEI for yield among the 18 representative genotypes by reducing the relative effect of GEI compared with genotypic variance, and helped to identify opportunities to improve breeding and germplasm-testing strategies for this region.

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The temperature variation of the 3’Cl n.q.r. frequencies in 3,5- and 2,3- dichloroanisoles has been reported here. Both compounds show two lines each, and these have been assigned to the two chlorines in the same molecule with the help of the additive model for the substituent effect. The temperature dependence has been analysed in terms of Bayer-Kushida-Brown model.The torsional frequencies and their temperature dependence have been calculated numerically under a two-mode approximation. 0.n comparing the results in 3,5-dichloroanisole with those in 3,5-dichlorophenol it can be seen that they show similar behaviour owing to the absence of hydrogen bonding in both.

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Genome-wide association studies show strong evidence of association with endometriosis for markers on chromosome 1p36 spanning the potential candidate genes WNT4, CDC42 and LINC00339. WNT4 is involved in development of the uterus, and the expression of CDC42 and LINC00339 are altered in women with endometriosis. We conducted fine mapping to examine the role of coding variants in WNT4 and CDC42 and determine the key SNPs with strongest evidence of association in this region. We identified rare coding variants in WNT4 and CDC42 present only in endometriosis cases. The frequencies were low and cannot account for the common signal associated with increased risk of endometriosis. Genotypes for five common SNPs in the region of chromosome 1p36 show stronger association signals when compared with rs7521902 reported in published genome scans. Of these, three SNPs rs12404660, rs3820282, and rs55938609 were located in DNA sequences with potential functional roles including overlap with transcription factor binding sites for FOXA1, FOXA2, ESR1, and ESR2. Functional studies will be required to identify the gene or genes implicated in endometriosis risk.

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Infrared spectra of 1,3-dithiole-2-thione (DTT) and its four selenium analogues have been studied in the region 4000 to 20 cm�1. Assignment of all the fundamental frequencies was made by noting the band shifts on progressive selenation. Normal coordinate analysis procedures have been applied for both in-plane and out-of-plane vibrations to help the assignments. The Urey�Bradley force function supplemented with valence force constants for the out-of-plane vibrations was employed for coordinate calculations. A correlation of the infrared assignments of DTT with its different selenium analogues is accomplished. Further, the infrared assignments are compared with those of trithiocarbonate ion and its selenium analogues and other structurally related heterocyclic molecules.

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The system equations of a collisionless, unmagnetized plasma, contained in a box where a high frequency (h.f.1 electric field is incident, are solved in the electrostatic approximation. The surface modes of the plasma in the semi-infinite and box geometry are investigated. In the high frequency limit, the mode frequencies are not significantly changed by the h.f. field but their group velocities can be quite different. Two long wavelength low frequency modes, which are not excited in the absence of h.f. field, are found. These modes are true surface modes (decaying on one wavelength from the surface) unlike the only low frequency ion acoustic mode in the zero field case. In the short wavelength limit the low frequency mode occurs at &/2, oi being the ion plasma frequency, a result similar to the case of no h.f. field.

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The hydromagnetic Kelvin-Helmholtz (K-H) instability problem is studied for a three-layered system analytically by arriving at the marginal instability condition. As the magnetic field directions are taken to vary in the three regions, both the angle and finite thickness effects are seen on the instability criterion. When the relative flow speed of the plasmas on the two sides of the interfaces separating the inner and the surrounding layers is U < Uc, where Uc is the critical speed, the system is stable both for symmetric and asymmetric perturbations. However, unlike the case of the interface bounded by two semiinfinite media, Uc is no longer the minimum critical speed above which the system will be unstable for all wavenumbers; another critical speed U* > Uc is introduced due to the finiteness of the system. When Uc < U < U*, the instability can set in either through the symmetric or asymmetric mode, depending on the ratio of the plasma parameters and angle between the magnetic field directions across the boundaries. The instability arises for a finite range of wavenumbers, thus giving rise to the upper and lower cut-off frequencies for the spectra of hydromagnetic surface waves generated by the K-H instability mechanism. When U > U*, both the modes are unstable for short wavelengths. The results are finally used to explain some observational features of the dependence of hydromagnetic energy spectra in the magnetosphere on the interplanetary parameters.

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Pharmacogenetics deals with genetically determined variation in drug response. In this context, three phase I drug-metabolizing enzymes, CYP2D6, CYP2C9, and CYP2C19, have a central role, affecting the metabolism of about 20-30% of clinically used drugs. Since genes coding for these enzymes in human populations exhibit high genetic polymorphism, they are of major pharmacogenetic importance. The aims of this study were to develop new genotyping methods for CYP2D6, CYP2C9, and CYP2C19 that would cover the most important genetic variants altering the enzyme activity, and, for the first time, to describe the distribution of genetic variation at these loci on global and microgeographic scales. In addition, pharmacogenetics was applied to a postmortem forensic setting to elucidate the role of genetic variation in drug intoxications, focusing mainly on cases related to tricyclic antidepressants, which are commonly involved in fatal drug poisonings in Finland. Genetic variability data were obtained by genotyping new population samples by the methods developed based on PCR and multiplex single-nucleotide primer extension reaction, as well as by collecting data from the literature. Data consisted of 138, 129, and 146 population samples for CYP2D6, CYP2C9, and CYP2C19, respectively. In addition, over 200 postmortem forensic cases were examined with respect to drug and metabolite concentrations and genotypic variation at CYP2D6 and CYP2C19. The distribution of genetic variation within and among human populations was analyzed by descriptive statistics and variance analysis and by correlating the genetic and geographic distances using Mantel tests and spatial autocorrelation. The correlation between phenotypic and genotypic variation in drug metabolism observed in postmortem cases was also analyzed statistically. The genotyping methods developed proved to be informative, technically feasible, and cost-effective. Detailed molecular analysis of CYP2D6 genetic variation in a global survey of human populations revealed that the pattern of variation was similar to those of neutral genomic markers. Most of the CYP2D6 diversity was observed within populations, and the spatial pattern of variation was best described as clinal. On the other hand, genetic variants of CYP2D6, CYP2C9, and CYP2C19 associated with altered enzymatic activity could reach extremely high frequencies in certain geographic regions. Pharmacogenetic variation may also be significantly affected by population-specific demographic histories, as seen within the Finnish population. When pharmacogenetics was applied to a postmortem forensic setting, a correlation between amitriptyline metabolic ratios and genetic variation at CYP2D6 and CYP2C19 was observed in the sample material, even in the presence of confounding factors typical for these cases. In addition, a case of doxepin-related fatal poisoning was shown to be associated with a genetic defect at CYP2D6. Each of the genes studied showed a distinct variation pattern in human populations and high frequencies of altered activity variants, which may reflect the neutral evolution and/or selective pressures caused by dietary or environmental exposure. The results are relevant also from the clinical point of view since the genetic variation at CYP2D6, CYP2C9, and CYP2C19 already has a range of clinical applications, e.g. in cancer treatment and oral anticoagulation therapy. This study revealed that pharmacogenetics may also contribute valuable information to the medicolegal investigation of sudden, unexpected deaths.

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STUDY QUESTION Is there a contribution of the minor allele at the KRAS single nucleotide polymorphism (SNP) rs61764370 in the let-7 microRNA-binding site to endometriosis risk? SUMMARY ANSWER We found no evidence for association between endometriosis risk and rs61764370 or any other SNPs in KRAS. WHAT IS KNOWN ALREADY The rs61764370 SNP in the 3' untranslated region of the KRAS gene is predicted to disrupt a complementary binding site (LCS6) for the let-7 microRNA, and was recently reported to be at a high frequency (31%) in 132 women of varying ancestry with endometriosis compared with frequencies in a database of population controls (up to 7.6% depending on ancestry), suggesting a strong effect of this KRAS SNP in the aetiology of endometriosis. STUDY DESIGN, SIZE AND DURATION This was a case-control study with a total of 11 206 subjects. The study was performed between February 2012 and July 2012. PARTICIPANTS/MATERIALS, SETTINGAND METHODS We first investigated a possible association between common markers in KRAS and endometriosis risk from our genome-wide association (GWA) data in 3194 surgically confirmed endometriosis cases and 7060 controls of European ancestry. Although rs61764370 was not genotyped on the GWA arrays, five SNPs typed in the study were highly correlated with this variant. The rs61764370 and two SNPs highly correlated with rs61764370 were then genotyped in 933 endometriosis cases and 952 controls using the Sequenom MassARRAY platform. MAIN RESULTS AND THE ROLE OF CHANCE There was no evidence for an association between rs61764370 and endometriosis risk P = 0.411 and odds ratio = 1.10 (95% confidence intervals: 0.88-1.36). We also found no evidence for an association between the highly correlated SNP rs17387019 and endometriosis. Their minor allele frequencies in cases and controls were of 0.087-0.091 similar to the population frequency reported previously for this variant in controls. Analyses of endometriosis cases with revised American Fertility Society stage III/IV disease also showed no evidence for an association between these SNPs and endometriosis risk. LIMITATIONS AND REASONS FOR CAUTION The GWA and genotyped data sets were not independent since individuals and cases from some families overlap. Controls in our GWA study were not screened for endometriosis. WIDER IMPLICATIONS OF THE FINDINGS The key SNP, rs61764370, was genotyped in a subset of samples. Our results do not support the suggestion that carrying the minor allele at rs61764370 contributes to a significant number of endometriosis cases and rs61764370 is, therefore, unlikely to be a useful marker of endometriosis risk. STUDY FUNDING/COMPETING INTEREST(S) The research was funded by grants from the Australian National Health and Medical Research Council and Wellcome Trust. None of the authors has competing interests for the study.

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The male-to-female sex ratio at birth is constant across world populations with an average of 1.06 (106 male to 100 female live births) for populations of European descent. The sex ratio is considered to be affected by numerous biological and environmental factors and to have a heritable component. The aim of this study was to investigate the presence of common allele modest effects at autosomal and chromosome X variants that could explain the observed sex ratio at birth. We conducted a large-scale genome-wide association scan (GWAS) meta-analysis across 51 studies, comprising overall 114 863 individuals (61 094 women and 53 769 men) of European ancestry and 2 623 828 common (minor allele frequency >0.05) single-nucleotide polymorphisms (SNPs). Allele frequencies were compared between men and women for directly-typed and imputed variants within each study. Forward-time simulations for unlinked, neutral, autosomal, common loci were performed under the demographic model for European populations with a fixed sex ratio and a random mating scheme to assess the probability of detecting significant allele frequency differences. We do not detect any genome-wide significant (P < 5 x 10(-8)) common SNP differences between men and women in this well-powered meta-analysis. The simulated data provided results entirely consistent with these findings. This large-scale investigation across ~115 000 individuals shows no detectable contribution from common genetic variants to the observed skew in the sex ratio. The absence of sex-specific differences is useful in guiding genetic association study design, for example when using mixed controls for sex-biased traits.

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Thermal characterization of surface-micromachined microheaters is carried out from their dynamic response to electrothermal excitations. An electrical equivalent circuit model is developed for the thermo-mechanical system. The mechanical parameters are extracted from the frequency response obtained using a laser Doppler vibrometer. The resonant frequencies of the microheaters are measured and compared with FEM simulations. The thermal time constants are obtained from the electrical equivalent model by fitting the model response to the measured frequency response. Microheaters with an active area of 140 µm × 140 µm have been realized on two different layers (poly-1 and poly-2) with two different air gaps (2 µm and 2.75 µm). The effective time constants, combining thermal and mechanical responses, are in the range of 0.13–0.22 ms for heaters on the poly-1 layer and 1.9 µs–0.15 ms for microheaters on the poly-2 layer. The thermal time constants of the microheaters are in the range of a few microseconds, thus making them suitable for sensor applications that need a faster thermal response.

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Association mapping seeks to identify marker alleles present at significantly different frequencies in cases carrying a particular disease or trait compared with controls. Genome-wide association studies are increasingly replacing candidate gene-based association studies for complex diseases, where a number of loci are likely to contribute to disease risk and the effect size of each particular risk allele is typically modest or low. Good study design is essential to the success of an association study, and factors such as the heritability of the disease under investigation, the choice of controls, statistical power, multiple testing and whether the association can be replicated need to be considered before beginning. Likewise, thorough quality control of the genotype data needs to be undertaken prior to running any association analyses. Finally, it should be kept in mind that a significant genetic association is not proof positive that a particular genetic locus causes a disease, but rather an important first step in discovering the genetic variants underlying a complex disease.

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Much of the global cancer research is focused on the most prevalent tumors; yet, less common tumor types warrant investigation, since A rare disorder is not necessarily an unimportant one . The present work discusses a rare tumor type, the benign adenomas of the pituitary gland, and presents the advances which, during the course of this thesis work, contributed to the elucidation of a fraction of their genetic background. Pituitary adenomas are benign neoplasms of the anterior pituitary lobe, accounting for approximately 15% of all intracranial tumors. Pituitary adenoma cells hypersecrete the hormones normally produced by the anterior pituitary tissue, such as growth hormone (GH) and prolactin (PRL). Despite their non-metastasizing nature, these adenomas can cause significant morbidity and have to be adequately treated; otherwise, they can compromise the patient s quality of life, due to conditions provoked by hormonal hypersecretion, such as acromegaly in the case of GH-secreting adenomas, or due to compressive effects to surrounding tissues. The vast majority of pituitary adenomas arise sporadically, whereas a small subset occur as component of familial endocrine-related tumor syndromes, such as Multiple Endocrine Neoplasia type 1 (MEN1) and Carney complex (CNC). MEN1 is caused by germline mutations in the MEN1 tumor suppressor gene (11q13), whereas the majority of CNC cases carry germline mutations in the PRKAR1A gene (17q24). Pituitary adenomas are also encountered in familial settings outside the context of MEN1 and CNC, but unlike in the latter syndromes, their genetic background until recently remained elusive. Evidence in previous literature supported the notion that a tumor suppressor gene on 11q13, residing very close to but still distinct from MEN1, causes genetic susceptibility to pituitary tumors. The aim of the study was to identify the genetic cause of a low penetrance form of Pituitary Adenoma Predisposition (PAP) in families from Northern Finland. The present work describes the methodological approach that led to the identification of aryl hydrocarbon receptor interacting protein (AIP) as the gene causing PAP. Combining chip-based technologies (SNP and gene expression arrays) with traditional gene mapping methods and genealogy data, we showed that germline AIP mutations cause PAP in familial and sporadic settings. PAP patients were diagnosed with mostly adenomas of the GH/PRL-secreting cell lineage. In Finland, two AIP mutations accounted for 16% of all patients diagnosed with GH-secreting adenomas, and for 40% of patients being younger than 35 years of age at diagnosis. AIP is suggested to act as a tumor suppressor gene, a notion supported by the nature of the identified mutations (most are truncating) and the biallelic inactivation of AIP in the tumors studied. AIP has been best characterized as a cytoplasmic interaction partner of aryl hydrocarbon receptor (AHR), also known as dioxin receptor, but it has other partners as well. The mechanisms that underlie AIP-mediated pituitary tumorigenesis are to date largely unknown and warrant further investigation. Because AIP was identified in the genetically homogeneous Finnish population, it was relevant to examine its contribution to PAP in other, more heterogeneous, populations. Analysis of pituitary adenoma patient series of various ethnic origins and differing clinical settings revealed germline AIP mutations in all cohorts studied, albeit with low frequencies (range 0.8-7.4%). Overall, PAP patients were typically diagnosed at a young age (range 8-41 years), mainly with GH-secreting adenomas, without strong family history of endocrine disease. Because many PAP patients did not display family history of pituitary adenomas, detection of the condition appeared challenging. AIP immunohistochemistry was tested as a molecular pre-screening tool on mutation-positive versus mutation-negative tumors, and proved to be a potentially useful predictor of PAP. Mutation screening of a large cohort of colorectal, breast, and prostate tumors did not reveal somatic AIP mutations. These tumors, apart from being the most prevalent among men and women worldwide, have been associated with acromegaly, particularly colorectal neoplasia. In this material, AIP did not appear to contribute to the pathogenesis of these common tumor types and other genes seem likely to play a role in such tumorigenesis. Finally, the contribution of AIP in pediatric onset pituitary adenomas was examined in a unique population-based cohort of sporadic pituitary adenoma patients from Italy. Germline AIP mutations may account for a subset of pediatric onset GH-secreting adenomas (in this study one of seven GH-secreting adenoma cases or 14.3%), and appear to be enriched among young (≤25 years old) patients. In summary, this work reveals a novel tumor susceptibility gene, namely AIP, which causes genetic predisposition to pituitary adenomas, in particular GH-secreting adenomas. Moreover, it provides molecular tools for identification of individuals predisposed for PAP. Further elaborate studies addressing the functional role of AIP in normal and tumor cells will hopefully expand our knowledge on endocrine neoplasia and reveal novel cellular mechanisms of pituitary tumorigenesis, including potential drug targets.

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Observations were made on a nest of Ropalidia cyathiformis consisting of three combs. The number of eggs, larvae, pupae and adults were monitored at about 3-day intervals for a 2-month period. The behaviour of the adults was observed with special reference to the proportion of time spent on each of the three combs, the proportion of time spent away from the nest site and the frequencies of dominance interactions and egg laying. The adults moved freely between the three combs suggesting that all of them and all the three combs belonged to one nest. However, most of the adults preferred combs 2 and 3 over comb 1. Of the 10 animals chosen for a detailed analysis of behaviour, seven spent varying periods of time away from the nest site and oRen brought back food or building material. Five of the 10 animals laid at least one egg each but two adults monopolized most of the egg-laying. The animals showed a variety of dominance interactions on the basis of which they have been arranged in a dominance hierarchy. The dominant individuals laid most of the eggs and spent little or no time foraging, while the subordinate individuals spent more time foraging and laid few eggs or none. It is argued that R. cyathiformis is different from R. marginata, the only other Indian social wasp whose behaviour has been studied, in being at a more primitive stage of social organization.

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Background: The Ewing sarcoma family of tumors (ESFT) are rare but highly malignant neoplasms that occur mainly in bone or but also in soft tissue. ESFT affects patients typically in their second decade of life, whereby children and adolescents bear the heaviest incidence burden. Despite recent advances in the clinical management of ESFT patients, their prognosis and survival are still disappointingly poor, especially in cases with metastasis. No targeted therapy for ESFT patients is currently available. Moreover, based merely on current clinical and biological characteristics, accurate classification of ESFT patients often fails at the time of diagnosis. Therefore, there is a constant need for novel molecular biomarkers to be applied in tandem with conventional parameters to further intensify ESFT risk-stratification and treatment selection, and ultimately to develop novel targeted therapies. In this context, a greater understanding of the genetics and immune characteristics of ESFT is needed. Aims: This study sought to open novel insights into gene copy number changes and gene expression in ESFT and, further, to enlighten the role of inflammation in ESFT. For this purpose, microarrays were used to provide gene-level information on a genomewide scale. In addition, this study focused on screening of 9p21.3 deletion sizes and frequencies in ESFT and, in another pediatric cancer, acute lymphocytic leukemia (ALL), in order to define more exact criteria for highrisk patient selection and to provide data for developing a more reliable diagnostic method to detect CDKN2A deletions. Results: In study I, 20 novel ESFT-associated suppressor genes and oncogenes were pinpointed using combined array CGH and expression analysis. In addition, interesting chromosomal rearrangements were identified: (1) Duplication of derivative chromosome der(22)(11;22) was detected in three ESFT patients. This duplication included the EWSR1-FLI1 fusion gene leading to increase in its copy number; (2) Cryptic amplifications on chromosomes 20 and 22 were detected, suggesting a novel translocation between chromosomes 20 and 22, which most probably produces a fusion between EWSR1 and NFATC2. In study II, bioinformatic analysis of ESFT expression profiles showed that inflammatory gene activation is detectable in ESFT patient samples and that the activation is characterized by macrophage gene expression. Most interestingly, ESFT patient samples were shown to express certain inflammatory genes that were prognostically significant. High local expression of C5 and JAK1 at the tumor site was shown to associate with favorable clinical outcome, whereas high local expression of IL8 was shown to be detrimental. Studies III and IV showed that the smallest overlapping region of deletion in 9p21.3 includes CDKN2A in all cases and that the length of this region is 12.2 kb in both Ewing sarcoma and ALL. Furthermore, our results showed that the most widely used commercial CDKN2A FISH probe creates false negative results in the narrowest microdeletion cases (<190 kb). Therefore, more accurate methods should be developed for the detection of deletions in the CDKN2A locus. Conclusions: This study provides novel insights into the genetic changes involved in the biology of ESFT, in the interaction between ESFT cells and immune system, and in the inactivation of CDKN2A. Novel ESFT biomarker genes identified in this study serve as a useful resource for future studies and in developing novel therapeutic strategies to improve the survival of patients with ESFT.

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Identification of genes predisposing to tumor syndromes has raised general awareness of tumorigenesis. Genetic testing of tumor susceptibility genes aids the recognition of individuals at increased risk of tumors. Identification of novel predisposing genes enables further studies concerning the classification of potential associated tumors and the definition of target patient group. Pituitary adenomas are common, benign neoplasms accounting for approximately 15% of all intracranial tumors. Accurate incidence estimation is challenging since a great portion of these adenomas are small and asymptomatic. Clinically relevant adenomas, that cause symptoms due to the expansion of the cell mass or the over-secretion of normally produced hormones, occur in approximately one of 1 000 individuals. Although the majority of pituitary adenomas are sporadic, a minority occur as components of familial syndromes, such as Multiple Endocrine Neoplasia type 1 (MEN1) and Carney complex (CNC). MEN1 syndrome is caused by germ-line mutations in the MEN1 gene, whereas most of the CNC patients carry the mutated protein kinase A (PKA) regulatory subunit-1-α (PRKAR1A) gene. Recently, other conditions predisposing to endocrine tumors have been identified: Pituitary Adenoma Predisposition (PAP) and MEN type 4 (MEN4). PAP was originally identified in a genetically homogeneous Finnish population. In a population based cohort from Northern Finland, aryl hydrocarbon receptor-interacting protein (AIP) gene mutations were found in 16% of all patients diagnosed with growth hormone (GH) producing pituitary adenoma, and in 40% of the subset of patients who were diagnosed under the age of 35 years. Since AIP mutations were originally described in a defined, homogeneous population from Northern Finland, it was relevant to study whether mutations also occur in more heterogeneous populations. In patient cohorts with different ethnic origins and variable clinical phenotypes, germ-line AIP mutations were detectable at low frequencies (range 0.8-7.4%). AIP mutation-positive patients were often diagnosed with a GH-producing adenoma at a young age, and usually had no family history of endocrine tumors. The low frequency of AIP mutations in randomly selected patients, and the lack of any family history of pituitary adenomas create a challenge for the identification of PAP patients. Our preliminary study suggests that AIP immunohistochemistry may serve as a pre-screening tool to distinguish between the AIP mutation-negative and the mutation-positive tumors. Tumors of various endocrine glands are components of MEN1 and CNC syndromes. Somatic MEN1 and PRKAR1A mutations in sporadic pituitary adenomas are rare, but occur in some of the other tumors related to these syndromes. The role of AIP mutations in endocrine neoplasia was studied and our results indicated that somatic AIP mutations are rare or non-existent in sporadic tumors of endocrine glands (0 of 111). Furthermore, germ-line AIP mutations in prolactin producing adenomas (2 of 9) confirmed the role of this pituitary tumor type in the PAP phenotype. Thyroid disorders are common in the general population, and the majority of them are sporadic. Interestingly, it has been suggested that thyroid disorders might be more common in PAP families. For this reason we studied germ-line AIP mutations in 93 index cases from familial non-medullary thyroid cancer (NMTC) families. The underlying gene or genes for familial NMTC have not been identified yet. None of the patients had any potentially pathogenic AIP mutation. This suggests that AIP is unlikely to play a role in familial NMTCs. A novel multiple endocrine syndrome was originally described in rats with phenotypic features of human MEN type 1 and 2. Germ-line mutations of cyclin-dependent kinase inhibitor 1B (CDKN1B also known as p27Kip1) gene were reported later in these rats and a germ-line mutation was also identified in one human family with MEN1-like phenotype (later named MEN4). To confirm the importance of this gene’s mutations in humans, we performed a mutation screening in MEN-like patients and in patients with pituitary adenoma. Our results indicate that CDKN1B/p27Kip1 mutations appear in a small portion of MEN1-like patients (one of 36), and that such mutations are rare or non-existent in both familial (0 of 19) and sporadic pituitary adenoma patients (0 of 50). In conclusion, this work strengthens the tumor susceptibility role of AIP and CDKN1B/p27Kip1 in endocrine neoplasia. Clarifying the PAP phenotype facilitates the identification of potential AIP mutation carriers. Genetic counseling can be offered to the relatives and follow-up of the mutation carriers can be organized, hence an earlier diagnosis is feasible.