Variants in genes encoding small GTPases and association with epithelial ovarian cancer susceptibility

Epithelial ovarian cancer (EOC) is the fifth leading cause of cancer mortality in American women. Normal ovarian physiology is intricately connected to small GTP binding proteins of the Ras superfamily (Ras, Rho, Rab, Arf, and Ran) which govern processes such as signal transduction, cell proliferation, cell motility, and vesicle transport. We hypothesized that common germline variation in genes encoding small GTPases is associated with EOC risk. We investigated 322 variants in 88 small GTPase genes in germline DNA of 18,736 EOC patients and 26,138 controls of European ancestry using a custom genotype array and logistic regression fitting log-additive models. Functional annotation was used to identify biofeatures and expression quantitative trait loci that intersect with risk variants. One variant, ARHGEF10L (Rho guanine nucleotide exchange factor 10 like) rs2256787, was associated with increased endometrioid EOC risk (OR=1.33, p=4.46 x 10-6). Other variants of interest included another in ARHGEF10L, rs10788679, which was associated with invasive serous EOC risk (OR=1.07, p=0.00026) and two variants in AKAP6 (A-kinase anchoring protein 6) which were associated with risk of invasive EOC (rs1955513, OR=0.90, p=0.00033; rs927062, OR =0.94, p=0.00059). Functional annotation revealed that the two ARHGEF10L variants were located in super-enhancer regions and that AKAP6 rs927062 was associated with expression of GTPase gene ARHGAP5 (Rho GTPase activating protein 5). Inherited variants in ARHGEF10L and AKAP6, with potential transcriptional regulatory function and association with EOC risk, warrant investigation in independent EOC study populations

Mutation analysis of BRCA1, BRCA2, PALB2 and BRD7 in a hospital-based series of German patients with triple-negative breast cancer

Abstract Triple-negative breast cancer (TNBC) is an aggressive form of breast carcinoma with a poor prognosis. Recent evidence suggests that some patients with TNBC harbour germ-line mutations in DNA repair genes which may render their tumours susceptible to novel therapies such as treatment with PARP inhibitors. In the present study, we have investigated a hospitalbased series of 40 German patients with TNBC for the presence of germ-line mutations in BRCA1, BRCA2, PALB2, and BRD7 genes. Microfluidic array PCR and next-generation sequencing was used for BRCA1 and BRCA2 analysis while conventional high-resolution melting and Sanger sequencing was applied to study the coding regions of PALB2 and BRD7, respectively. Truncating mutations in BRCA1 were found in six patients, and truncating mutations in BRCA2 and PALB2 were detected in one patient each, whereas no truncating mutation was identified in BRD7. One patient was a double heterozygote for the PALB2 mutation, c.758insT, and a BRCA1 mutation, c.927delA. Our results confirm in a hospital-based setting that a substantial proportion of German TNBC patients (17.5%) harbour germ-line mutations in genes involved in homologydirected DNA repair, with a preponderance of BRCA1 mutations. Triple-negative breast cancer should be considered as an additional criterion for future genetic counselling and diagnostic sequencing

Mutation Analysis of <em>BRCA1, BRCA2, PALB2</em> and <em>BRD7</em> in a Hospital-Based Series of German Patients with Triple-Negative Breast Cancer

<div><p>Triple-negative breast cancer (TNBC) is an aggressive form of breast carcinoma with a poor prognosis. Recent evidence suggests that some patients with TNBC harbour germ-line mutations in DNA repair genes which may render their tumours susceptible to novel therapies such as treatment with PARP inhibitors. In the present study, we have investigated a hospital-based series of 40 German patients with TNBC for the presence of germ-line mutations in <em>BRCA1</em>, <em>BRCA2</em>, <em>PALB2</em>, and <em>BRD7</em> genes. Microfluidic array PCR and next-generation sequencing was used for <em>BRCA1</em> and <em>BRCA2</em> analysis while conventional high-resolution melting and Sanger sequencing was applied to study the coding regions of <em>PALB2</em> and <em>BRD7</em>, respectively. Truncating mutations in <em>BRCA1</em> were found in six patients, and truncating mutations in <em>BRCA2</em> and <em>PALB2</em> were detected in one patient each, whereas no truncating mutation was identified in <em>BRD7</em>. One patient was a double heterozygote for the <em>PALB2</em> mutation, c.758insT, and a <em>BRCA1</em> mutation, c.927delA. Our results confirm in a hospital-based setting that a substantial proportion of German TNBC patients (17.5%) harbour germ-line mutations in genes involved in homology-directed DNA repair, with a preponderance of <em>BRCA1</em> mutations. Triple-negative breast cancer should be considered as an additional criterion for future genetic counselling and diagnostic sequencing.</p> </div

Truncating mutations in <i>BRCA1</i>, <i>BRCA2</i> and <i>PALB2</i> among 40 TNBC patients.

<p>Truncating mutations in <i>BRCA1</i>, <i>BRCA2</i> and <i>PALB2</i> among 40 TNBC patients. Mutations were designated according to the improved mutation nomenclature recommended by the Human Genome Variation Society (<a href="http://www.hgvs.org/mutnomen/" target="_blank">www.hgvs.org/mutnomen/</a>). AD = age at diagnosis, BC = breast cancer, OC = ovarian cancer, IHC = immunohistochemistry, n.a. = not applicable.</p>*<p>BIC database as from Sep 29, 2010 (<a href="http://research.nhgri.nih.gov/projects/bic/Member/index.shtml" target="_blank">http://research.nhgri.nih.gov/projects/bic/Member/index.shtml</a>), accessed on July 10, 2012.</p

Double heterozygosity for <i>BRCA1</i> and <i>PALB2</i> mutations.

<p>A case with digenic mutations in <i>BRCA1</i> (left) and <i>PALB2</i> (right). Left: Heterozygosity for mutation c.927delA in exon 10 of the <i>BRCA1</i> gene. Right: Heterozygosity for mutation c.758insT in exon 4 of the <i>PALB2</i> gene. The sense strand is shown in both electropherograms.</p

Neocytolisis: A space born concept of erythrocyte-removal falsified in the Swiss Alps

Neocytolysis is the preferred destruction of young red blood cells (neocytes) when there are too many erythrocytes. This happens during space flight or when descending after a prolonged sojourn at high altitude. We carried out a prospective study at the Jungfraujoch Research Station (3450 m) with the aim to prove the existence of neocytolysis for the first time. Newly formed erythrocytes from 12 male test persons were marked in Heidelberg (110 m) and during a 19-day stay at 3450 m altitude by glycine labelled with non-radioactive isotopes. The elimination dynamics for erythrocytes produced in normoxia and at high altitude did not differ. Together with changes of reticulocyte counts the concept of neocytolysis could be falsified

Moderate altitude but not additional endurance training increases markers of oxidative stress in exhaled breath condensate

Oxidative stress occurs at altitude, and physical exertion might enhance this stress. In the present study, we investigated the combined effects of exercise and moderate altitude on redox balance in ten endurance exercising biathletes, and five sedentary volunteers during a 6-week-stay at 2,800 m. As a marker for oxidative stress, hydrogen peroxide (H(2)O(2)) was analyzed by the biosensor measuring system Ecocheck, and 8-iso prostaglandin F2alpha (8-iso PGF2alpha) was determined by enzyme immunoassay in exhaled breath condensate (EBC). To determine the whole blood antioxidative capacity, we measured reduced glutathione (GSH) enzymatically using Ellman's reagent. Exercising athletes and sedentary volunteers showed increased levels of oxidative markers at moderate altitude, contrary to our expectations; there was no difference between both groups. Therefore, all subjects' data were pooled to examine the oxidative stress response exclusively due to altitude exposure. H(2)O(2) levels increased at altitude and remained elevated for 3 days after returning to sea level (p </= 0.05). On the other hand, 8-iso PGF2alpha levels showed a tendency to increase at altitude, but declined immediately after returning to sea level (p </= 0.001). Hypoxic exposure during the first day at altitude resulted in elevated GSH levels (p </= 0.05), that decreased during prolonged sojourn at altitude (p </= 0.001). In conclusion, a stay at moderate altitude for up to 6 weeks increases markers of oxidative stress in EBC independent of additional endurance training. Notably, this oxidative stress is still detectable 3 days upon return to sea level