Mapping the Von Hippel -- Lindau disease tumour suppressor gene: identification of germline deletions by pulsed field gel electrophoresis

Von Hlppel—Lindau (VHL) disease is a dominantly Inheritedfamillal cancer syndrome In which affected individuals havea greatly increased predisposition to the development of haemangloblastomasof the central nervous system and retina, renal cell carcinomaand phaeochromocytoma. The VHL gene has been mapped to chromosome3p25 -p26 by genetic linkage studies and we have previouslydemonstrated that the VHL gene is tightly linked to the D3S601locus (Zmax = 18.86 at     

An association between variants in the IGF2 gene and Beckwith-Wiedemann syndrome: interaction between genotype and epigenotype

Beckwith-Wiedemann syndrome (BWS) is a fetal overgrowth disorder involving the deregulation of a number of genes, including IGF2 and CDKN1C, in the imprinted gene cluster on chromosome 11p15.5. In sporadic BWS cases the majority of patients have epimutations in this region. Loss of imprinting of the IGF2 gene is frequently observed in BWS, as is reduced CDKN1C expression related to loss of maternal allele-specific methylation (LOM) of the differentially methylated region KvDMR1. The causes of epimutations are unknown, although recently an association with assisted reproductive technologies has been described. To date the only genetic mutations described in BWS are in the CDKN1C gene. In order to screen for other genetic predispositions to BWS, the conserved sequences between human and mouse differentially methylated regions (DMRs) of the IGF2 gene were analyzed for variants. Four single nucleotide polymorphisms (SNPs) were found in DMR0 (T123C, G358A, T382G and A402G) which occurred in three out of 16 possible haplotypes: TGTA, CATG and CAGA. DNA samples from a cohort of sporadic BWS patients and healthy controls were genotyped for the DMR0 SNPs. There was a significant increase in the frequency of the CAGA haplotype and a significant decrease in the frequency of the CATG haplotype in the patient cohort compared to controls. These associations were still significant in a BWS subgroup with KvDMR1 LOM, suggesting that the G allele at T382G SNP (CAGA haplotype) is associated with LOM at KvDMR1. This indicates either a genetic predisposition to LOM or interactions between genotype and epigenotype that impinge on the disease phenotype.     

Reproducibility of new classification schemes for the pathology of ductal carcinoma in situ of the breast.

AIM: To compare the interobserver variation in the pathological classification of ductal carcinoma in situ of the breast using two recently proposed classification schemes. METHODS: 11 pathologists classified a set of 25 cases of ductal carcinoma in situ chosen to reflect a range of lesions, using the traditional architectural classification together with the modified cytonuclear grading scheme of Holland et al and the Van Nuys classification scheme. Participating pathologists received a standard tutorial, written information, and illustrative photomicrographs before their assessment of the cases. RESULTS: Interobserver agreement was poorest when using the architectural scheme (kappa = 0.44), largely owing to variations in classifying lesions with a mixed component of patterns (kappa = 0.13). Agreement was better using the modified cytonuclear grading scheme (kappa = 0.57), with most consistency achieved using the Van Nuys scheme (kappa = 0.66). Most discordant results using the later scheme were due to inconsistency in assessing the presence or absence of luminal necrosis. CONCLUSIONS: Both the new classification schemes assessed in this study were an improvement over the traditional architectural classification system for ductal carcinoma in situ, and resulted in more reproducible pathological assignment of cases. The Van Nuys classification scheme is easy to apply, even to small areas of carcinoma, resulting in acceptable interobserver agreement between reporting pathologists. Additional work will be required to arrive at a consensus definition of necrosis for cases in the non-high-grade group.     

Immunohistochemical evidence for mesothelial origin of paratesticular adenomatoid tumour

AIMS: To investigate the histogenesis of paratesticular adenomatoid tumour by use of immunohistochemical markers for a variety of carcinomas and mesothelioma. METHODS AND RESULTS: Immunohistochemical staining of sections from 12 cases of paratesticular adenomatoid tumour was undertaken using primary antibodies to antigens expressed by benign epithelial cells and carcinoma (cytokeratin AE1/AE3, cytokeratin 34ssE12, epithelial membrane antigen, MOC-31, Ber-EP4, CEA, B72.3, LEA.135, Leu M1), stromal and vascular markers (vimentin, CD34, factor VIII), and mesothelioma-associated antigens (thrombomodulin, HBME-1, OC 125) and p53 protein. There was absence of immunohistochemical expression of epithelial/carcinoma markers MOC-31, Ber-EP4, CEA, B72.3, LEA.135, Leu M1 and to factor VIII and CD34. All tumours expressed cytokeratin AE1/AE3, epithelial membrane antigen and vimentin, with weak expression of cytokeratin 34ssE12 in 25% of tumours. Each tumour showed expression of thrombomodulin, HBME-1 and OC 125 in a membranous distribution. p53 protein expression was not detected. CONCLUSIONS: The immunohistochemical profile of paratesticular adenomatoid tumour is strongly supportive of a mesothelial cell origin.     

Molecular analysis of de novo germline mutations in the von Hippel-Lindau disease gene

VHL disease is a dominantly inherited familial cancer syndromewith variable expression and age-dependent penetrance. The diagnosisof isolated cases is often delayed compared with familial cases,and estimates of the new mutation rate have varied more than20-fold. To investigate the frequency and origin of de novoVHL gene mutations we have analysed: (i) families with identicalmutations to determine if there is a common haplotype, and (ii)apparent new mutation cases to determine whether the clinicaldiagnosis of such cases is reliable and to define the parentalorigin of de novo VHL gene mutations. Haplotyping of 12 VHLmutations occurring in two or more families (total 42 kindreds)revealed that for most mutations there was no evidence of afounder effect. A marked bias for a paternal origin of new mutationshas been reported in other familial cancer syndromes such asneurofibromatosis type 1 (NF1), multiple endocrine neoplasia(MEN) 2B and bilateral retinoblastoma, but it is unclear whetherthis bias results from a greater susceptibility for mutagenesisduring male gametogenesis because of the larger number of celldivisions compared with that in oogenesis, or from genomic imprintingeffects. Analysis of 13 de novo VHL mutations in which the parentof origin could be established, showed no evidence for a biasfor a paternal origin (seven paternal, six maternal), and differedsignificantly from that reported in NF1, MEN2B and bilateralretinoblastoma. This result demonstrates that an increased susceptibilityto paternal allele mutation is not a universal finding in autosomalgenetic diseases and that the origin of new mutations may beinfluenced by both genomic imprinting effects and the increasednumber of cell divisions in spermatogenesis compared with oogenesis.     

Nucleolar organizer regions and prognosis in renal cell carcinoma

The prognostic significance of nucleolar organizer regions (NORs) in renal cell carcinoma (RCC) was evaluated. NORs were quantified in a series of 182 cases of RCC using the silver-colloid method. The cases were staged according to Robson's method (48 stage I, 26 stage II, 33 stage III, 75 stage IV) and mean NOR numbers for each tumour were correlated with survival over a 5-year period. Localized tumours (stages I and II) with low NOR numbers had an almost 100 per cent 5-year survival. Those patients with clinical evidence of metastases at presentation showed a high mortality, although those with low numbers of NORs had a significantly increased disease-free interval. Statistical analysis using the log rank test indicated NORs to be a significant predictor of survival over the whole series (P = 0.0001) and within each of Robson's stages (P = 0.0008 stage I, P = 0.0154 stage II, P = 0.0009 stage III, P = 0.0001 stage IV). Analysis of data using Cox's proportional hazard model showed mean NOR numbers to be independent of stage as a predictor of survival.     

Antimicrobial peptides play a functional role in bumblebee anti-trypanosome defense

Bumblebees, amongst the most important of pollinators, are under enormous population pressures. One of these is disease. The bumblebee and its gut trypanosome Crithidia bombi are one of the fundamental models of ecological immunology. Although there is previous evidence of increased immune gene expression upon Crithidia infection, recent work has focussed on the bumblebee’s gut microbiota. Here, by knocking down gene expression using RNAi, we show for the first time that antimicrobial peptides (AMPs) have a functional role in anti-Crithidia defense.     

A Model of First‐responder Coping: An Approach/Avoidance Bifurcation

The work of first responders is fraught with numerous stressors, ranging from potentially traumatic critical incidents to institutional strains. The severity and pervasiveness of these difficulties prompt a necessary consideration of the coping methods employed by first responders. The present study developed an empirical model of first‐responder coping strategies, based upon a nationally representative survey sample of 6240 first responders. Participants were drawn from Swedish first responders in the following occupations: coast guard, customs control, military, emergency medical services, fire department and police services. In the final model, exposure to stress related to well‐being through several indirect paths that in sum accounted for the original direct relationship between these constructs. These several indirect paths were classified theoretically as either approach or avoidance coping behaviours or subsequent health outcomes. In general, approach coping behaviours were related to better well‐being; and avoidance was related to a decrease in the outcome. The size of the present sample, as well as the diverse nature of the included first responders, suggests that the resulting model may offer a unique insight into potentially adaptive pathways for first‐responder coping. Copyright © 2016 John Wiley & Sons, Ltd.