Determination Of Gene Copy Number Research Articles

Comparison of a quantitative Real-Time PCR assay and droplet digital PCR for copy number analysis of the CCL4L genes

The controversy surrounding the findings that copy number variation, of the CCL3 encoding genes, influences HIV-1 infection and disease progression has been in part attributed to the variable results obtained from methods used for copy number evaluation. Like CCL3, the genes encoding the CC chemokine CCL4, also a natural ligand of the CCR5 receptor, are found to occur in population-specific multiple copy number and have been shown to play a protective role against HIV-1. This study evaluated the standard method of quantitative Real-Time PCR (qPCR) and droplet digital PCR (ddPCR) for CCL4L gene copy number determination. The CCL4 encoding genes are CCL4, occurring in two copies per diploid genome (pdg), and the non-allelic CCL4L genes, comprised of CCL4L1 and CCL4L2, which are both found in multiple copies pdg. Copy number of CCL4L, CCL4L1 and CCL4L2 was determined in a cohort of HIV-1-uninfected individuals from the South African Black (n=23) and Caucasian (n=32) population groups using qPCR and ddPCR. A stronger correlation between the number of CCL4L copies and the sum of CCL4L1 and CCL4L2 copies generated by ddPCR (r=0.99, p<0.0001) compared to qPCR (r=0.87, p<0.0001) was observed. Real-Time qPCR exhibited greater inaccuracy at higher copy numbers which is particularly relevant to our cohort of Black individuals who have a higher range of CCL4L copies (3–6) compared to Caucasians (0–4) and a higher population median (4 and 2, respectively). Medians and ranges of CCL4L1 (Black: 2, 0–4, Caucasian: 0, 0–2) and CCL4L2 (Black: 2, 1–5, Caucasian: 2, 0–3) were also higher in the Black population. Droplet digital PCR was shown to be a far superior method to qPCR for assessment of CCL4 gene copy number variation, the accuracy of which is essential for studies of the contribution of variable gene copy number to phenotypic outcomes of host infection and disease course.

TCEB3C a putative tumor suppressor gene of small intestinal neuroendocrine tumors

Small intestinal neuroendocrine tumors (SI-NETs), formerly known as midgut carcinoids, are rare and slow-growing neoplasms. Frequent loss of one copy of chromosome 18 in primary tumors and metastases has been observed. The aim of the study was to investigate a possible role of TCEB3C (Elongin A3), currently the only imprinted gene on chromosome 18, as a tumor suppressor gene in SI-NETs, and whether its expression is epigenetically regulated. Primary tumors, metastases, the human SI-NET cell line CNDT2.5, and two other cell lines were included. Immunohistochemistry, gene copy number determination by PCR, colony formation assay, western blotting, real-time quantitative RT-PCR, RNA interference, and quantitative CpG methylation analysis by pyrosequencing were performed. A large majority of tumors (33/43) showed very low to undetectable Elongin A3 expression and as expected 89% (40/45) displayed one gene copy of TCEB3C. The DNA hypomethylating agent 5-aza-2'-deoxycytidine induced TCEB3C expression in CNDT2.5 cells, in primary SI-NET cells prepared directly after surgery, but not in two other cell lines. Also siRNA to DNMT1 and treatment with the general histone methyltransferase inhibitor 3-deazaneplanocin A induced TCEB3C expression in a cell type-specific way. CpG methylation at the TCEB3C promoter was observed in all analyzed tissues and thus not related to expression. Overexpression of TCEB3C resulted in a 50% decrease in clonogenic survival of CNDT2.5 cells, but not of control cells. The results support a putative role of TCEB3C as a tumor suppressor gene in SI-NETs. Epigenetic repression of TCEB3C seems to be tumor cell type-specific and involves both DNA and histone methylation.

Determination of Transgene Copy Number in Stably Transfected Mammalian Cells by PCR-Capillary Electrophoresis Assay

The quantitative determination of transgene copy number in stably transfected mammalian cells has been traditionally estimated by Southern blot analysis. Recently, other methods have become available for appraisal of gene copy number, such as real-time PCR. Herein we describe a new method based on a fluorescently labeled PCR, followed by capillary electrophoresis. We amplified our target gene (prothrombin) and the internal control originating from genomic DNA (18S rRNA) in the same PCR tube and calculated the mean peak height ratio of the target:control gene for every cell clone sample. With this approach we identified stably transfected cell clones bearing the same transgene copy number. The results of our assay were confirmed by real-time PCR. Our method proves to be fast, low-cost, and reproducible compared with traditionally used methods. This assay can be used as a rapid screening tool for the determination of gene copy number in gene expression experiments.

Direct Evaluation of the Effect of Gene Dosage on Secretion of Protein from Yeast Pichia pastoris by Expressing EGFP

Increasing the gene copy number has been commonly used to enhance the protein expression level in the yeast Pichia pastoris. However, this method has been shown to be effective up to a certain gene copy number, and a further increase of gene dosage can result in a decrease of expression level. Evidences indicate the gene dosage effect is product-dependent, which needs to be determined when expressing a new protein. Here, we describe a direct detection of the gene dosage effect on protein secretion through expressing the enhanced green fluorescent protein (EGFP) gene under the direction of the α-factor preprosequence in a panel of yeast clones carrying increasing copies of the EGFP gene (from one to six copies). Directly examined under fluorescence microscopy, we found relatively lower levels of EGFP were secreted into the culture medium at one copy and two copies, substantial improvement of secretion appeared at three copies, plateau happened at four and five copies, and an apparent decrease of secretion happened at six copies. The secretion of EGFP being limiting at four and five copies was due to abundant intracellular accumulation of proteins, observed from the fluorescence image of yeast and confirmed by western blotting, which significantly activated the unfolded protein response indicated by the up-regulation of the BiP (the KAR2 gene product) and the protein disulfide isomerase. This study implies that tagging a reporter like GFP to a specific protein would facilitate a direct and rapid determination of the optimal gene copy number for high-yield expression.

Determination of HSV-1 UL5 and UL29 gene copy numbers in an HSV complementing Vero cell line

The genetic stability of transgenes is a critical characteristic used to assess constructed cell lines used for vaccine production. The evaluation of gene copy numbers by a qPCR method, is one of the most common approaches used to assess the consistency of transgenes in a constructed cell line. The cell line AV529-19 is a Vero-based cell line specifically engineered to express the HSV-1 UL5 and UL29 open reading frames. AV529-19 is used to support the replication of a defective HSV-2 viral candidate vaccine called HSV529. To assess the genetic stability of the UL5 and UL29 transgenes in AV529-19 cells, a digital PCR-based approach was developed. During characterization of the test method, the specificity, accuracy, and intermediate precision of the assay was investigated based on regulatory guidelines. The developed assay was used to monitor the stability of the transgenes in the manufactured AV529-19 cell lines by comparison of transgene copy numbers in the master cell bank (MCB) with their copy numbers in the extended cell bank (ECB). Results showed that the UL29 and UL5 transgenes are stable in that there are one and three copies of the UL29 and UL5 genes, respectively, per cell in both the AV529-19 MCB and ECB.

Abstract 49: Agreement of immunohistochemistry, fluorescence in situ hybridization, real-time quantitative polymerase-chain reaction, and quantitative reverse transcriptase PCR for Her-2/Neu status assessment in breast cancer patients: a single center, retrospective m

Abstract Background: Immunohistochemistry (IHC) and fluorescence-in-situ hybridization (FISH) are the standard methods to assess human epidermal growth factor receptor 2 (HER-2) status in breast cancer (BC) patients. Real-time quantitative polymerase-chain-reaction (Q-PCR) and quantitative reverse transcriptase PCR (qRT-PCR) allow quantitative determination of gene copy number and gene expression on, respectively, DNA and RNA. These molecular methods are available to assess HER-2 amplification/overexpression but their use remains controversial. Here we performed a parallel comparison of these four methods to define their concordance rates and evaluate their relative role in HER-2 status determination. Patients and Methods: HER-2 status was determined by IHC, FISH, Q-PCR and qRT-PCR in a retrospectively assessed cohort of 130 BC patients. The studied set was enriched in cases scoring as 3+ by standard IHC analysis. Tests were performed blindly in parallel. Western blotting was performed on a subset of equivocal cases. Kappa statistics and ROC curves were used as appropriate, and concordance analyses were interpreted according to the ASCO/CAP guidelines. Results: Of the 130 enrolled patients, 47 (36%) were classified as positive and 27 (21%) as equivocal by IHC. With FISH, 50 patients (38%) were HER-2 amplified, while 80 (62%) were not. The overall agreement between FISH and Q-PCR was 98.5% (95% CI, 94.6% to 99.6%) with a k value of 0.97 (95% CI, 0.92 to 1). Assuming FISH as the standard reference, Q-PCR showed a sensitivity of 98% (95% CI, 89.5% to 99.6%) and a specificity of 98.8% (95% CI, 93.3% to 99.8%), with a global accuracy of 98%. The overall agreement between FISH and qRT-PCR was 96.9% (95% CI, 92.3% to 98.8%) with a k value of 0.94 (95% CI, 0.87 to 1). For both comparisons, the observed concordance values were greater than the 95% threshold required by the ASCO/CAP guidelines to validate novel approaches for HER-2 testing. 3% of samples showed HER-2 overexpression only by qRT-PCR analysis, in all cases belonging to the equivocal range as defined by either IHC or FISH. In these patients, WB confirmed higher HER-2 protein levels compared to healthy diploid controls. Conclusions: The high concordance between FISH and both Q-PCR and qRT-PCR supports the use of molecular tests as an alternative to current standard methods. Present results also suggest that qRT-PCR may be able to unequivocally classify patients belonging to the IHC/FISH equivocal range. Non-amplified HER-2 overexpressing BCs may account for the rare trastuzumab-responders observed in phase III trials, where trastuzumab response was assessed in HER-2-amplified vs. non-amplified cases. Citation Format: Gabriele Zoppoli, Anna Garuti, Ilaria Rocco, Claudia Palermo, Gabriella Cirmena, Enrico Carminati, Daniele Friedman, Ludovica Verdun di Cantogno, Anna Sapino, Franco Patrone, Alberto Ballestrero. Agreement of immunohistochemistry, fluorescence in situ hybridization, real-time quantitative polymerase-chain reaction, and quantitative reverse transcriptase PCR for Her-2/Neu status assessment in breast cancer patients: a single center, retrospective m [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 49. doi:10.1158/1538-7445.AM2013-49

High Frequency Spontaneous Deletions within the IcaADBC Operon of Clinical Staphylococcus epidermidis Isolates.

Staphylococcus epidermidis has been shown to undergo a phase variation correlating with expression of the icaADBC operon which contributes to biofilm formation. Biofilm formation of Enterococcus faecalis is related to heterogeneity in electrophoretic mobility. Here the relationship between phase variants of clinical isolates of S. epidermidis, icaADBC presence and electrophoretic mobility distributions is investigated. Of 105 S. epidermidis clinical isolates, 5 showed phase variation on Congo Red agar plate. Biofilm forming capability of the black colonies and inability of the red colonies were confirmed using a microtiter plate assay and confocal laser scanning microscopy. Upon analysis of electrophoretic mobility distributions, the black colonies displayed heterogeneity at pH 2 which was absent in the red colonies of the same strain. Surprisingly, it was shown that in all red colonies had lost the icaADBC genes. Determination of gene copy number using Real Time PCR targeting icaA showed reduction of gene copy within a culture with phase variation. In conclusion, using three fundamentally different approaches phase variation of the five clinical isolates was observed. Variants appeared through loss of icaA and icaC gens. To our knowledge this is the first report indicating S. epidermidis strains irreversible switching from biofilm + to biofilm – phenotype by deletion of ica genes. Key words: deletion, ica genes, Staphylococcus epidermidis, IcaADBC operon

Abstract 2993: Comparison of copy number variation using exome sequencing and affymetrix SNP6.0 genotype array in human cancer cell lines

Abstract Whole exome sequencing has been used successfully as a cost effective and unbiased method in the detection of single nucleotide variants (SNVs) in the coding regions of the human genome. Its application in identifying another class of genetic variability - copy number variation (CNV) - has been hindered by numerous factors including inconsistent exome capture probe specificity and efficiency for the target regions, discontinuous targets, and variable exon lengths etc. In the current work, we applied ExomeCNV, a depth-of-coverage based statistical analysis method developed by Sathirapongsauti et. al., to exome NGS data from a larger collection of cancer cell lines. The exomes were captured using Agilent SureSelect Human All Exon Kit and sequenced on the average depth of 70x using the Illumina HiSeq platform. To control for sequence coverage biases introduced by the capture technology, CNVs for each cancer cell line are presented as a ratio to a baseline control constructed using pooled samples processed in the same manner. Genotyping arrays are standard methods of choice for CNV discovery in cancer cell lines from the Cancer Genome Project by the Sanger Institute and the Cancer Cell Line Encyclopedia project by the Broad Institute. We obtained Affymetrix SNP6.0 genotype data for the cancer cell lines from these two sources. CNVs detected from exome sequencing were compared with those discovered from genotyping arrays in the same set of cancer cell lines. We present here a comprehensive comparison of the cancer cell line gene copy number determination from exome sequencing and genotyping methods. Our results indicate that, with sufficient exome coverage and properly constructed controls, copy number detection using exome data is a valuable alternative to genotype based approach. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2993. doi:1538-7445.AM2012-2993

A Method for Measuring Gene Copy Number in Biological Samples without Using Control Samples of Known Copies

Various human diseases are caused by gene copy number variants, underlining the importance of determining disease gene copy number for clinical diagnostics. In this study, we describe a method for determining gene copy number in a biological organism. In this method, both a target gene and an internal control gene were amplified from the organism by regular PCR. The PCR products were purified and quantified, and the target and internal control genes were mixed at different molar ratios. Real-time PCR was then used to measure the quantification cycle (Cq) values of both the target and internal control genes in the mixtures. A standard curve was constructed to correlate the differences between the Cq values and the logarithmic ratios of the target gene to the internal control gene. Real-time PCR was then used to measure the Cq values of both the target and internal control genes in experimental samples; the copy number of the target gene in the sample can be calculated readily from the calculated standard curve. This method was validated by a set of internal control genes and a foreign gene in transgenic alfalfa, demonstrating the utility of this method in the determination of gene copy number for various applications.

Analysis of the copy number of exogenous genes in transgenic cotton using real-time quantitative PCR and the 2-△△CT method

Presence of multiple copies of a transgene has been found to associate with gene silencing that may manifest early or only over a period of time. As such, transgenic copy number should be analyzed as soon as possible. The commonly used method to analyze gene copy number, Southern blotting, has been found to be unreliable for determination of gene copy number when rearrangement or tandem repeats integration occurred. In recent years, a powerful real-time fluorescence quantitative real-time PCR (qRT-PCR) method has been used to analyze gene copy number in genetically modified plants, but these methods have also their own application conditions. Thus, based on real-time quantitative PCR technology, the modified 2-△△CT method, which has been used usually in analyzing gene expression, was used for the first time, to analyze transgenic copy numbers in transgenic cotton. In this paper, a single-copy homozygous transgenic plant whose identity was confirmed by Southern blotting using restriction enzymes was used as a calibrator. Genomic DNA that was extracted from the calibrator and six transgenic T0 cotton plants transformed by pollen tube pathway or gene gun bombardment was amplified by quantitative PCR, and the gene copy numbers were estimated by the modified 2-△△CT method to be 6, 3, 2, 2, 3 and 2 copies. In addition, except 6 copies all other identifications (3, 2, 2, 3 and 2) were equally indicated by the corresponding Southern blotting. This study supports the modified 2-△△CT method using quantitative real-time PCR technology to provide a fast, high-throughput method to analyze the copy number of foreign genes in a large transgenic T0 population. Key words: Cotton, transgene copy number, modified 2-△△CT method, Southern blotting.

Characterization and Quantitation of a Novel β-Lactamase Gene Found in a Wastewater Treatment Facility and the Surrounding Coastal Ecosystem

Wastewater treatment plants (WWTPs) are engineered structures that collect, concentrate, and treat human waste, ultimately releasing treated wastewater into local environments. While WWTPs efficiently remove most biosolids, it has been shown that many antibiotics and antibiotic-resistant bacteria can survive the treatment process. To determine how WWTPs influence the concentration and dissemination of antibiotic-resistant genes into the environment, a functional metagenomic approach was used to identify a novel antibiotic resistance gene within a WWTP, and quantitative PCR (qPCR) was used to determine gene copy numbers within the facility and the local coastal ecosystem. From the WWTP metagenomic library, the fosmid insert contained in one highly resistant clone (MIC, ≈ 416 μg ml(-1) ampicillin) was sequenced and annotated, revealing 33 putative genes, including a 927-bp gene that is 42% identical to a functionally characterized β-lactamase from Staphylococcus aureus PC1. Isolation and subcloning of this gene, referred to as bla(M-1), conferred ampicillin resistance to its Escherichia coli host. When normalized to volume, qPCR showed increased concentrations of bla(M-1) during initial treatment stages but 2-fold-decreased concentrations during the final treatment stage. The concentration ng(-1) DNA increased throughout the WWTP process from influent to effluent, suggesting that bla(M-1) makes up a significant proportion of the overall genetic material being released into the coastal ecosystem. Average discharge was estimated to be 3.9 × 10(14) copies of the bla(M-1) gene released daily into this coastal ecosystem. Furthermore, the gene was observed in all sampled coastal water and sediment samples surrounding the facility. Our results suggest that WWTPs may be a pathway for the dissemination of novel antibiotic resistance genes into the environment.

Complement and antibody primary immunodeficiency in juvenile systemic lupus erythematosus patients

To evaluate the frequency of primary immunodeficiencies (PID) in juvenile systemic lupus erythematosus (JSLE) patients. Some 72 JSLE patients were analyzed for levels of immunoglobulin classes and IgG subclasses and early components of the classical complement pathway. Determination of C4 gene copy number (GCN) and detection of type I C2 deficiency (D) were also performed. PID was identified in 16 patients (22%): C2D in three, C4D in three, C1qD in two, IgG2D (<20 mg/dl) in four, IgAD (<7 mg/dl) in three, and IgMD (<35 mg/dl) in three; one of these patients presented IgA, C2 and C4D. Two patients had low C4 GCN and two had type I C2D. Demographic data, family history of autoimmune disease and PID, JSLE clinical findings, occurrence of infections, disease activity and therapies were similar in patients with and without PID (p > 0.05). Remarkably, the median of Systemic Lupus International Collaborating Clinics/ACR-damage index (SLICC/ACR-DI) was significantly higher in JSLE patients with PID compared with patients without these abnormalities (p = 0.0033), likewise the high frequency of SLICC/ACR-DI > 1 (p = 0.023). A high frequency of PID was observed in JSLE patients, suggesting that these defects may contribute to lupus development. Our findings indicate that these two groups of PID should be investigated in severe pediatric lupus.

Dual-color silver-enhanced in situ hybridization for assessing HER2 gene amplification in breast cancer

Amplification of the human epidermal growth factor receptor 2 (HER2) gene occurs in 20–25% of breast cancers, and is recognized as a prognostic and predictive marker. HER2 gene amplification, evaluated as a change in protein expression or gene copy number, can be identified by a number of methods. Fluorescence in situ hybridization (FISH) is considered the gold standard for HER2 gene copy number determination; however, a number of impediments prevent its wider use in a clinical setting. The aims of our study were to compare dual-color silver-enhanced in situ hybridization (SISH) with single-color SISH and FISH on formalin-fixed, paraffin-embedded sections, and to validate its use as a routine method for assessing HER2 status in breast cancers. A total of 146 invasive breast carcinoma cases were assessed for HER2 gene amplification by FISH and dual-color SISH. Dual-color SISH and FISH results exhibited a concordance rate of 97% (κ=0.912). A comparison of the single-color SISH method with dual-color SISH showed that 142 of 146 cases were in agreement (97%, κ=0.930). Our results showed that dual-color SISH is a viable alternative to FISH that offers a number of advantages in a clinical setting.

Molecular Profiling of Cancer—The Future of Personalized Cancer Medicine: A Primer on Cancer Biology and the Tools Necessary to Bring Molecular Testing to the Clinic

Cancers arise as a result of an accumulation of genetic aberrations that are either acquired or inborn. Virtually every cancer has its unique set of molecular changes. Technologies have been developed to study cancers and derive molecular characteristics that increasingly have implications for clinical care. Indeed, the identification of key genetic aberrations (molecular drivers) may ultimately translate into dramatic benefit for patients through the development of highly targeted therapies. With the increasing availability of newer, more powerful, and cheaper technologies such as multiplex mutational screening, next generation sequencing, array-based approaches that can determine gene copy numbers, methylation, expression, and others, as well as more sophisticated interpretation of high-throughput molecular information using bioinformatics tools like signatures and predictive algorithms, cancers will routinely be characterized in the near future. This review examines the background information and technologies that clinicians and physician-scientists will need to interpret in order to develop better, personalized treatment strategies.

Determination of Beta-Defensin Genomic Copy Number in Different Populations: A Comparison of Three Methods

BackgroundThere have been conflicting reports in the literature on association of gene copy number with disease, including CCL3L1 and HIV susceptibility, and β-defensins and Crohn's disease. Quantification of precise gene copy numbers is important in order to define any association of gene copy number with disease. At present, real-time quantitative PCR (QPCR) is the most commonly used method to determine gene copy number, however the Paralogue Ratio Test (PRT) is being used in more and more laboratories.FindingsIn this study we compare a Pyrosequencing-based Paralogue Ratio Test (PPRT) for determining beta-defensin gene copy number with two currently used methods for gene copy number determination, QPCR and triplex PRT by typing five different cohorts (UK, Danish, Portuguese, Ghanaian and Czech) of DNA from a total of 576 healthy individuals. We found a systematic measurement bias between DNA cohorts revealed by QPCR, but not by the PRT-based methods. Using PRT, copy number ranged from 2 to 9 copies, with a modal copy number of 4 in all populations.ConclusionsQPCR is very sensitive to quality of the template DNA, generating systematic biases that could produce false-positive or negative disease associations. Both triplex PRT and PPRT do not show this systematic bias, and type copy number within the correct range, although triplex PRT appears to be a more precise and accurate method to type beta-defensin copy number.

Diffuse large B-cell lymphomas with CDKN2A deletion have a distinct gene expression signature and a poor prognosis under R-CHOP treatment: a GELA study

AbstractGenomic alterations play a crucial role in the development and progression of diffuse large B-cell lymphomas (DLBCLs). We determined gene copy number alterations (GCNAs) of TP53, CDKN2A, CDKN1B, BCL2, MYC, REL, and RB1 with a single polymerase chain reaction (PCR) assay (quantitative multiplex PCR of short fragments [QMPSF]) in a cohort of 114 patients with DLBCL to assess their prognostic value and relationship with the gene expression profile. Losses of TP53 and CDKN2A, observed in 8% and 35% of patients, respectively, were significantly associated with a shorter survival after rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) treatment, independently of the International Prognostic Index and of the cell of origin. Analysis of the 9p21 genomic region indicated that transcripts encoding p14ARF and p16INK4A were both disrupted in most patients with CDKN2A deletion. These patients predominantly had an activated B-cell profile and showed a specific gene expression signature, characterized by dysregulation of the RB/E2F pathway, activation of cellular metabolism, and decreased immune and inflammatory responses. These features may constitute the molecular basis sustaining the unfavorable outcome and chemoresistance of this DLBCL subgroup. Detection of TP53 and CDKN2A loss by QMPSF is a powerful tool that could be used for patient stratification in future clinical trials.

388 Ductal carcinoma in situ of the breast: interobserver reproducibility of three classification schemes

Biomarkers play an essential role in the management of patients with invasive breast cancer. For selecting patients likely to respond to endocrine therapy, both oestrogen receptors (ERs) and progesterone receptors (PRs) should be measured on all newly diagnosed invasive breast cancers. On the other hand, for selecting likely response to all forms of anti-HER2 therapy (trastuzumab, pertuzumab, lapatinib or ado-trastuzumab emtansine), determination of HER2 expression or gene copy number is mandatory. Where feasible, measurement of ER, PR and HER2 should be performed on recurrent lesions and the primary invasive tumour. Although methodological problems exist in the determination of Ki67, because of its clearly established clinical value, wide availability and low costs relative to the available multianalyte signatures, Ki67 may be used for determining prognosis, especially if values are low or high. In oestrogen receptor (ER)-positive, HER2-negative, lymph node–negative patients, multianalyte tests such as urokinase plasminogen activator (uPA)-PAI-1, Oncotype DX, MammaPrint, EndoPredict, Breast Cancer Index (BCI) and Prosigna (PAM50) may be used to predict outcome and aid adjunct therapy decision-making. Oncotype DX, MammaPrint, EndoPredict and Prosigna may be similarly used in patients with 1–3 metastatic lymph nodes. All laboratories measuring biomarkers for patient management should use analytically and clinically validated assays, participate in external quality assurance programs, have established assay acceptance and rejection criteria, perform regular audits and be accredited by an appropriate organisation.

Mosaicism in Osteopathia Striata with Cranial Sclerosis

Osteopathia striata with cranial sclerosis is an X-linked dominant condition caused by mutations in the WTX gene, resulting in linear striations in long bones in combination with cranial sclerosis. This condition is usually lethal in males. OBJECTIVE/PATIENT: Our aim was to determine the underlying genetic cause in a 37-yr-old male with this condition. DNA sequencing of peripheral blood and hair was performed to identify mutations in WTX. Quantitative PCR was performed to determine gene copy number variation. DNA sequenced from peripheral blood revealed the presence of two alleles at the 1108th position of the WTX gene. Subsequent DNA sequencing of hair follicles and quantitative PCR confirmed the presence of mosaicism. A novel mutation (c.1108G>T) found in our patient results in a truncated protein (E370X). Our patient represents the first confirmed case of mosaicism in osteopathia striata with cranial sclerosis.

Simple and accurate determination of CYP2D6 gene copy number by a loop-mediated isothermal amplification method and an electrochemical DNA chip

Background A combination technology of a loop-mediated isothermal amplification (LAMP) method and an electrochemical DNA chip has been developed. In this study, the CYP2D6 gene copies were detected by this technology for determination of the functional CYP2D6*5 and CYP2D6*2 × 2 alleles. Methods A set of LAMP primers was designed to coamplify the CYP2D6 gene, but not the CYP2D6*36, and the CYP2D8P gene, which would enable determination of the CYP2D6 gene copies by relatively comparing with the amount of the amplified products of CYP2D6 and CYP2D8P. The LAMP products were reacted with the electrochemical DNA chip using the DNA detection system Genelyzer™ that automatically controls hybridization reaction, washing, and electrochemical detection. To test the feasibility of the system, 16 samples that have various combinations of copy numbers were selected from pooled samples previously genotyped according to empirically well-authorized Southern blotting-based RFLP methods. Results The CYP2D6 gene copies were consistent with the previous genotypes except a rare CYP2D6*18 allele probably due to mutation near the primer region. The results were completely reproducible in a blind test and were given within 1.5 h. Conclusions This method offers a simple and accurate determination of the CYP2D6 gene copies and is expected to contribute to personalized medicine.

Industrial fuel ethanol yeasts contain adaptive copy number changes in genes involved in vitamin B1 and B6 biosynthesis

Fuel ethanol is now a global energy commodity that is competitive with gasoline. Using microarray-based comparative genome hybridization (aCGH), we have determined gene copy number variations (CNVs) common to five industrially important fuel ethanol Saccharomyces cerevisiae strains responsible for the production of billions of gallons of fuel ethanol per year from sugarcane. These strains have significant amplifications of the telomeric SNO and SNZ genes, which are involved in the biosynthesis of vitamins B6 (pyridoxine) and B1 (thiamin). We show that increased copy number of these genes confers the ability to grow more efficiently under the repressing effects of thiamin, especially in medium lacking pyridoxine and with high sugar concentrations. These genetic changes have likely been adaptive and selected for in the industrial environment, and may be required for the efficient utilization of biomass-derived sugars from other renewable feedstocks.