Population distribution and ancestry of the cancer protective MDM2 SNP285 (rs117039649).

The MDM2 promoter SNP285C is located on the SNP309G allele. While SNP309G enhances Sp1 transcription factor binding and MDM2 transcription, SNP285C antagonizes Sp1 binding and reduces the risk of breast-, ovary- and endometrial cancer. Assessing SNP285 and 309 genotypes across 25 different ethnic populations (>10.000 individuals), the incidence of SNP285C was 6-8% across European populations except for Finns (1.2%) and Saami (0.3%). The incidence decreased towards the Middle-East and Eastern Russia, and SNP285C was absent among Han Chinese, Mongolians and African Americans. Interhaplotype variation analyses estimated SNP285C to have originated about 14,700 years ago (95% CI: 8,300 - 33,300). Both this estimate and the geographical distribution suggest SNP285C to have arisen after the separation between Caucasians and modern day East Asians (17,000 - 40,000 years ago). We observed a strong inverse correlation (r = -0.805; p < 0.001) between the percentage of SNP309G alleles harboring SNP285C and the MAF for SNP309G itself across different populations suggesting selection and environmental adaptation with respect to MDM2 expression in recent human evolution. In conclusion, we found SNP285C to be a pan-Caucasian variant. Ethnic variation regarding distribution of SNP285C needs to be taken into account when assessing the impact of MDM2 SNPs on cancer risk.

CTF meeting 2012: Translation of the basic understanding of the biology and genetics of NF1, NF2, and schwannomatosis toward the development of effective therapies.

The neurofibromatoses (NF) are autosomal dominant genetic disorders that encompass the rare diseases NF1, NF2, and schwannomatosis. The NFs affect more people worldwide than Duchenne muscular dystrophy and Huntington's disease combined. NF1 and NF2 are caused by mutations of known tumor suppressor genes (NF1 and NF2, respectively). For schwannomatosis, although mutations in SMARCB1 were identified in a subpopulation of schwannomatosis patients, additional causative gene mutations are still to be discovered. Individuals with NF1 may demonstrate manifestations in multiple organ systems, including tumors of the nervous system, learning disabilities, and physical disfigurement. NF2 ultimately can cause deafness, cranial nerve deficits, and additional severe morbidities caused by tumors of the nervous system. Unmanageable pain is a key finding in patients with schwannomatosis. Although today there is no marketed treatment for NF-related tumors, a significant number of clinical trials have become available. In addition, significant preclinical efforts have led to a more rational selection of potential drug candidates for NF trials. An important element in fueling this progress is the sharing of knowledge. For over 20 years the Children's Tumor Foundation has convened an annual NF Conference, bringing together NF professionals to share novel findings, ideas, and build collaborations. The 2012 NF Conference held in New Orleans hosted over 350 NF researchers and clinicians. This article provides a synthesis of the highlights presented at the conference and as such, is a "state-of-the-field" for NF research in 2012.

Increased rate of missense/in-frame mutations in individuals with NF1-related pulmonary stenosis: a novel genotype-phenotype correlation.

Neurofibromatosis type 1 (NF1) and its related disorders (NF1-Noonan syndrome (NFNS) and Watson syndrome (WS)) are caused by heterozygous mutations in the NF1 gene. Pulmonary stenosis (PS) occurs more commonly in NF1 and its related disorders than in the general population. This study investigated whether PS is associated with specific types of NF1 gene mutations in NF1, NFNS and WS. The frequency of different NF1 mutation types in a cohort of published and unpublished cases with NF1/NFNS/WS and PS was examined. Compared with NF1 in general, NFNS patients had higher rates of PS (9/35=26% vs 25/2322=1.1%, P value<0.001). Stratification according to mutation type showed that the increased PS rate appears to be driven by the NFNS group with non-truncating mutations. Eight of twelve (66.7%) NFNS cases with non-truncating mutations had PS compared with a 1.1% PS frequency in NF1 in general (P<0.001); there was no increase in the frequency of PS in NFNS patients with truncating mutations. Eight out of eleven (73%) individuals with NF1 and PS, were found to have non-truncating mutations, a much higher frequency than the 19% reported in NF1 cohorts (P<0.015). Only three cases of WS have been published with intragenic mutations, two of three had non-truncating mutations. Therefore, PS in NF1 and its related disorders is clearly associated with non-truncating mutations in the NF1 gene providing a new genotype-phenotype correlation. The data indicate a specific role of non-truncating mutations on the NF1 cardiac phenotype.

Hormone replacement therapy and breast cancer.

There is evidence that hormone replacement therapy (HRT) may both stimulate and inhibit breast cancers, giving rise to a spectrum of activities, which are frequently hard to understand. Here we summarise the evidence for these paradoxical effects and, given the current data, attempt to give an indication where it may or may not be appropriate to prescribe HRT.It is clear that administration of oestrogen-progestin (E-P) and oestrogen alone (E) HRT is sufficient to stimulate the growth of overt breast tumours in women since withdrawal of HRT results in reduction of proliferation of primary tumours and withdrawal responses in metastatic tumours. E-P, E including tibolone are associated with increased local and distant relapse when given after surgery for breast cancer. For women given HRT who do not have breast cancer the only large randomised trial (WHI) of E-P or E versus placebo has produced some expected and also paradoxical results. E-P increases breast cancer risk as previously shown in observational studies. Risk is increased, particularly in women known to be compliant. Conversely, E either has no effect or reduces breast cancer risk consistent with some but not all observational studies. Two observational studies report a decrease or at least no increase in risk when E-P or E are given after oophorectomy in young women with BRCA1/2 mutations. Early oophorectomy increases death rates from cardiovascular and other conditions and there is evidence that this may be reversed by the use of E post-oophorectomy. HRT may thus reduce the risk of breast cancer and other diseases (e.g., cardiovascular) in young women and increase or decrease them in older women.

Guidelines for colorectal cancer screening and surveillance in moderate and high risk groups (update from 2002).

The British Society of Gastroenterology (BSG) and the Association of Coloproctology for Great Britain and Ireland (ACPGBI) commissioned this update of the 2002 guidance. The aim, as before, is to provide guidance on the appropriateness, method and frequency of screening for people at moderate and high risk from colorectal cancer. This guidance provides some new recommendations for those with inflammatory bowel disease and for those at moderate risk resulting from a family history of colorectal cancer. In other areas guidance is relatively unchanged, but the recent literature was reviewed and is included where appropriate.

Pathogenesis of vestibular schwannoma in ring chromosome 22.

BACKGROUND: Ring chromosome 22 is a rare human constitutional cytogenetic abnormality. Clinical features of neurofibromatosis type 1 and 2 as well as different tumour types have been reported in patients with ring chromosome 22. The pathogenesis of these tumours is not always clear yet. METHODS: We report on a female patient with a ring chromosome 22 presenting with severe mental retardation, autistic behaviour, café-au-lait macules and facial dysmorphism. Peripheral blood lymphocytes were karyotyped and array CGH was performed on extracted DNA. At the age of 20 years she was diagnosed with a unilateral vestibular schwannoma. Tumour cells were analyzed by karyotyping, array CGH and NF2 mutation analysis. RESULTS: Karyotype on peripheral blood lymphocytes revealed a ring chromosome 22 in all analyzed cells. A 1 Mb array CGH experiment on peripheral blood DNA showed a deletion of 5 terminal clones on the long arm of chromosome 22. Genetic analysis of vestibular schwannoma tissue revealed loss of the ring chromosome 22 and a somatic second hit in the NF2 gene on the remaining chromosome 22. CONCLUSION: We conclude that tumours can arise by the combination of loss of the ring chromosome and a pathogenic NF2 mutation on the remaining chromosome 22 in patients with ring chromosome 22. Our findings indicate that patients with a ring 22 should be monitored for NF2-related tumours starting in adolescence.

Better life expectancy in women with BRCA2 compared with BRCA1 mutations is attributable to lower frequency and later onset of ovarian cancer.

PURPOSE: No formal assessment of life expectancy in women with BRCA1 and BRCA2 mutations in these genes has been reported previously. We have evaluated life expectancy using actuarial analysis and assessed the effect of breast and ovarian cancers on premature death in >1,000 BRCA1/2 carriers. METHODS: Families with pathogenic mutations in BRCA1 and BRCA2 have been ascertained in a 10-million population region of United Kingdom since 1996. Mutation carriers and their first-degree relatives were used in an analysis of breast and ovarian cancer incidence and mortality as well as to derive and compare an actuarial assessment of life expectancy. RESULTS: Six hundred twelve BRCA1 and 482 BRCA2 female mutation carriers were identified from 482 families. Life expectancy was significantly reduced for BRCA1 carriers compared with BRCA2 (P = 0.0002). This effect was attributable to an increased death rate from ovarian cancer (P = 0.04). Kaplan-Meier analysis revealed a better long-term survival from early-stage ovarian cancer in BRCA2 carriers but no significant differences in deaths from breast cancer or from women presenting with late-stage ovarian cancer. There was no other major contributing cause to death other than breast/ovarian cancer in BRCA1/2 female carriers. CONCLUSION: Interventions to reduce ovarian cancer incidence are likely to have a greater effect on life expectancy in BRCA1 compared with BRCA2 carriers.