MAD2 downregulation in hypoxia is independent of promoter hypermethylation

Aberrant expression of the MAD2 protein has been linked to chromosomal instability, malignant transformation and chemoresistance. Although reduced MAD2 expression is well recognised in human cancer cell lines, the mechanism(s) underlying its downregulation remain elusive. The objective of this study was to establish the impact of hypoxia on MAD2 expression and to investigate the potential role of aberrant promoter methylation as a possible mechanism of MAD2 downregulation. For this purpose, three ovarian cancer cell lines, displaying differing levels of MAD2, were treated with chromatin modifying drugs, pre and post-hypoxia exposure and a DHPLC analysis of DNA promoter methylation carried out. We show that hypoxia induces downregulation of MAD2 expression, independently of MAD2 promoter methylation. We also show no evidence of MAD2 promoter methylation in breast and prostate cancer cells or in breast cancer clinical material. While our findings provide no evidence for MAD2 promoter methylation, we show a concomitant upregulation of p21 with downregulation of MAD2 in hypoxia. Our in vitro results were also confirmed in an ovarian cancer tissue microarray (TMA), where a reciprocal staining of MAD2 and CAIX was found in 21/60 (35%) of tumours. In summary, MAD2 downregulation may be a crucial mechanism by which hypoxic cells become chemorefractory. This stems from our previous work where we demonstrated that MAD2 downregulation induces cellular senescence, a viable cellular fate, with resultant cellular resistance to paclitaxel. Moreover, MAD2 downregulation could play a central role in the induction of chemoresistance in hypoxia, a key tumour microenvironment associated with chemoresistance.

Refining Risk Estimates Using Models (Chapter 4)

In 2004 nineteen scientists from fourteen institutions in seven countries
collaborated in the landmark study described in chapter 2 (Thomas et al., 2004a). This chapter provides an overview of results of studies published subsequently and assesses how much, and why, new results differ from those of Thomas et al.
Some species distribution modeling (SDM) studies are directly comparable to the Thomas et al. estimates. Others using somewhat different methods nonetheless illuminate whether the original estimates were of the right order of magnitude. Climate similarity models (Williams et al., 2007; Williams and Jackson, 2007), biome, and vegetation dynamic models (Perry and Enright, 2006) have also been
applied in the context of climate change, providing interesting opportunities
for comparison and cross-validation with results from SDMs.
This chapter concludes with an assessment of whether the range of extinction risk estimates presented in 2004 can be narrowed, and whether the mean estimate should be revised upward or downward. To set the stage for these analyses, the chapter begins with brief reviews of advances in climate modeling and species modeling since 2004.

BRCA1 Immunohistochemical Staining as a Prognostic Indicator in Uterine Serous Carcinoma

OBJECTIVES: The objective of this study was to investigate the relationship between BRCA1 protein expression, as determined by immunohistochemistry, and clinical outcome in uterine serous carcinoma (USC). METHODS: A tissue microarray containing duplicate cores of 73 cases of USC was immunohistochemically stained with mouse anti-BRCA1 (Ab-1) mouse monoclonal (MS110) antibody. The cores were scored in a semiquantitative manner evaluating both the distribution and intensity of nuclear staining. BRCA1 protein expression was correlated with progression-free survival. RESULTS: Seventy-two of 73 cases were assessable, and there was a statistically significant decreased progression-free survival for those cases exhibiting tumor cell nuclei staining of 76% or greater (P = 0.0023). CONCLUSIONS: Our study illustrates that a low level of BRCA1 protein expression is a favorable prognostic indicator in USC, similar to what is observed in high-grade serous ovarian carcinoma. Further studies should focus on the BRCA1 status of USCs at a molecular level and also investigate whether BRCA1 protein expression is associated with response to chemotherapy in USC.

Clinicopathological features of homologous recombination-deficient epithelial ovarian cancers: Sensitivity to PARP inhibitors, platinum, and survival

Up to 50% of epithelial ovarian cancers (EOC) display defects in the homologous recombination (HR) pathway. We sought to determine the ramifications of the homologous recombination-deficient (HRD) status on the clinicopathologic features, chemotherapy response, and survival outcomes of patients with EOCs. HR status was determined in primary cultures from ascitic fluid in 50 chemotherapy-naïve patients by a functional RAD51 immunofluorescence assay and correlated with in vitro sensitivity to the PARP inhibitor (PARPi), rucaparib. All patients went on to receive platinum-based chemotherapy; platinum sensitivity, tumor progression, and overall survival were compared prospectively in HR-competent versus HRD patients. Compared with HR-competent patients, the HRD group was predominantly serous with a higher median CA125 at presentation. HRD was associated with higher ex vivo PARPi sensitivity and clinical platinum sensitivity. Median follow-up duration was 14 months; patients in the HRD group had lower tumor progression rates at 6 months, lower overall/disease-specific death rates at 12 months, and higher median survival. We therefore suggest that HRD as predicted by a functional RAD51 assay correlates with in vitro PARPi sensitivity, clinical platinum sensitivity, and improved survival outcome.

Validation of Next Generation Sequencing Technologies in Comparison to Current Diagnostic Gold Standards for BRAF, EGFR and KRAS Mutational Analysis

Next Generation Sequencing (NGS) has the potential of becoming an important tool in clinical diagnosis and therapeutic decision-making in oncology owing to its enhanced sensitivity in DNA mutation detection, fast-turnaround of samples in comparison to current gold standard methods and the potential to sequence a large number of cancer-driving genes at the one time. We aim to test the diagnostic accuracy of current NGS technology in the analysis of mutations that represent current standard-of-care, and its reliability to generate concomitant information on other key genes in human oncogenesis. Thirteen clinical samples (8 lung adenocarcinomas, 3 colon carcinomas and 2 malignant melanomas) already genotyped for EGFR, KRAS and BRAF mutations by current standard-of-care methods (Sanger Sequencing and q-PCR), were analysed for detection of mutations in the same three genes using two NGS platforms and an additional 43 genes with one of these platforms. The results were analysed using closed platform-specific proprietary bioinformatics software as well as open third party applications. Our results indicate that the existing format of the NGS technology performed well in detecting the clinically relevant mutations stated above but may not be reliable for a broader unsupervised analysis of the wider genome in its current design. Our study represents a diagnostically lead validation of the major strengths and weaknesses of this technology before consideration for diagnostic use.

Identification of Gene Expression-Based Prognostic Markers in the Hematopoietic Stem Cells of Patients With Myelodysplastic Syndromes

The diagnosis of patients with myelodysplastic syndromes (MDS) is largely dependent on morphologic examination of bone marrow aspirates. Several criteria that form the basis of the classifications and scoring systems most commonly used in clinical practice are affected by operator-dependent variation. To identify standardized molecular markers that would allow prediction of prognosis, we have used gene expression profiling (GEP) data on CD34+ cells from patients with MDS to determine the relationship between gene expression levels and prognosis.

New genetic loci link adipose and insulin biology to body fat distribution

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms.

Genetic studies of body mass index yield new insights for obesity biology

Obesity is heritable and predisposes to many diseases. To understand the genetic basis of obesity better, here we conduct a genome-wide association study and Metabochip meta-analysis of body mass index (BMI), a measure commonly used to define obesity and assess adiposity, in up to 339,224 individuals. This analysis identifies 97 BMI-associated loci (P < 5 × 10(-8)), 56 of which are novel. Five loci demonstrate clear evidence of several independent association signals, and many loci have significant effects on other metabolic phenotypes. The 97 loci account for ∼2.7% of BMI variation, and genome-wide estimates suggest that common variation accounts for >20% of BMI variation. Pathway analyses provide strong support for a role of the central nervous system in obesity susceptibility and implicate new genes and pathways, including those related to synaptic function, glutamate signalling, insulin secretion/action, energy metabolism, lipid biology and adipogenesis.

FOXP3+ regulatory T-cell counts correlate with histological response in Crohn's colitis treated with infliximab

Crohn's disease is a chronic inflammatory bowel disease of unknown aetiology. Mucosal inflammatory dysregulation is likely important, with increased production of pro-inflammatory cytokines, including tumour necrosis factor alpha (TNFα). The chimeric monoclonal antibody, infliximab, inhibits TNFα and promotes intestinal mucosal healing. Despite this, many patients still require surgical intervention. Patients who have undergone colonic resection post-infliximab therapy, show markedly variable morphological response to treatment. FOXP3+ CD4+ regulatory T-cells have been shown to have a protective role in autoimmune/inflammatory diseases and their sequestration to the bowel is found in those treated with infliximab. We examined the immunohistochemical profile of lymphoid aggregates in tissue sections from post-infliximab Crohn's colitis resection specimens, classified as morphological responders or non-responders, defined in relation to the absence/presence of mucosal ulceration and active inflammation, and a control group. Results indicated no significant diffences in CD68-positive cell counts but increased FOXP3-positive (P = 0.02) and CD4-positive (P = 0.05) cell counts in responders versus non-responders. Untreated control scores were similar to non-responders. Although based on small study numbers, our results suggest an association between upregulation of FOXP3+/CD4+ regulatory T-cells and morphological response to infliximab therapy. This represents a possible quantitative methodology for monitoring therapeutic response to infliximab therapy, based on immunohistochemical evaluation of endoscopic biopsy specimens.

Epidermal growth factor receptor (EGFR), HER2 and insulin-like growth factor-1 receptor (IGF-1R) status in ovarian adult granulosa cell tumours

AIMS: Adult granulosa cell tumours (AGCTs) are uncommon ovarian sex cord-stromal tumours which recur following surgical removal in up to 50% of patients. Treatment options for recurrent and advanced stage AGCTs are limited, with poor response to chemotherapy and radiotherapy. We aimed to assess epidermal growth factor receptor (EGFR), HER2 and insulin-like growth factor-1 receptor (IGF-1R) status in AGCTs with a view to investigating whether or not these receptors might be potential therapeutic targets in these neoplasms.

METHODS AND RESULTS: Immunohistochemical staining for EGFR, HER2 and IGF-1R was undertaken in 31 AGCTs. Tumour DNA was also analysed for mutations in the tyrosine kinase domain of EGFR (exons 18-21) by Cobas mutation RT-PCR. Twenty-three of 31 (74%) AGCTs showed some degree of EGFR expression, generally with cytoplasmic or mixed membranous and cytoplasmic staining of variable intensity. Eleven of 27 (41%) cases exhibited strong membranous and cytoplasmic expression of IGF-1R. HER2 expression was not seen. No mutations were found in exons 18-21 of the EGFR gene in hot-spots of therapeutic relevance.

CONCLUSIONS: This study raises the possibility that anti-EGFR and/or anti-IGF-1R therapies may be of potential benefit in ovarian AGCTs, and this requires further study. Lack of known mutations within the tyrosine kinase domain of EGFR suggests that EGFR-related tyrosine kinase inhibitors may not be useful therapeutically.