Exome-wide benchmark of difficult-to-sequence regions using short-read next-generation DNA sequencing.

Next-generation DNA sequencing (NGS) in short-read mode has recently been used for genetic testing in various clinical settings. NGS data accuracy is crucial in clinical settings, and several reports regarding quality control of NGS data, primarily focusing on establishing NGS sequence read accuracy, have been published thus far. Variant calling is another critical source of NGS errors that remains unexplored at the single-nucleotide level despite its established significance. In this study, we used a machine-learning-based method to establish an exome-wide benchmark of difficult-to-sequence regions at the nucleotide-residue resolution using 10 genome sequence features based on real-world NGS data accumulated in The Genome Aggregation Database (gnomAD) of the human reference genome sequence (GRCh38/hg38). The newly acquired metric, designated the 'UNMET score,' along with additional lines of structural information from the human genome, allowed us to assess the sequencing challenges within the exonic region of interest using conventional short-read NGS. Thus, the UNMET score could provide a basis for addressing potential sequential errors in protein-coding exons of the human reference genome sequence GRCh38/hg38 in clinical sequencing.

The impact of PIK3CA mutations and PTEN expression on the effect of neoadjuvant therapy for postmenopausal luminal breast cancer patients.

BACKGROUND: There is pressing needs to find the biomarker in the selection of neoadjuvant therapy in postmenopausal luminal breast cancer patients. We examined the hypothesis that PIK3CA mutations and low phosphatase and tensin homolog (PTEN) expression affect the response to neoadjuvant therapy and prognosis in postmenopausal luminal breast cancer patients. METHODS: Postmenopausal patients with estrogen receptor-positive, human epidermal growth factor receptor 2-negative breast cancer, up to stage II, who underwent neoadjuvant chemotherapy (NAC; n = 60) or neoadjuvant endocrine therapy (NAE; n = 55) were selected. PIK3CA exon 9 and exon 20 mutations were screened by high resolution melting analysis and confirmed by Sanger sequence. PTEN expression was evaluated by immunohistochemistry. The relationships among PIK3CA mutations, PTEN expression, clinicopathological features, the pathological effect of neoadjuvant therapy, recurrence-free survival (RFS) and overall survival were analyzed. RESULTS: Among 115 patients, PIK3CA mutations and low PTEN expression before treatment were detected in 35 patients (30.4%) and in 28 patients (24.3%), respectively. In the NAC group, tumor with PIK3CA mutations showed significantly poorer response than tumor with PIK3CA wild-type (p = 0.03). On the other hand, in the NAE group, there was no significant difference in pathological therapeutic effect between tumor with PIK3CA mutations and tumor with PIK3CA wild-type (p = 0.54). In the NAC group, the log-rank test showed no difference in RFS between patients with PIK3CA mutations and PIK3CA wild-type (p = 0.43), but patients with low PTEN expression showed significantly worse RFS compared to patients with high PTEN expression (5 year RFS 0.64 vs. 0.87, p = 0.01). In the Cox proportional hazards model for RFS, PTEN expression, progesterone receptor, and pathological therapeutic effect were predictive factors for time to recurrence (All p < 0.05). CONCLUSIONS: PIK3CA mutations are associated with resistance to NAC but do not affect the response to NAE. Low PTEN expression does not affect response to either NAC or NAE but correlates with shorter RFS in patients who received NAC. These biomarkers will be further evaluated for clinical use to treat postmenopausal luminal breast cancer patients.

Multiplex PCR and multicolor probes melting for the simultaneous detection of five UGT1A1 variants.

The multiplex PCR melting analysis method was developed for detecting the five UGT1A1 variants. Multiplexing was achieved using color probes and Tm. The probes for *28/*6, *27, *29, and *7 were discriminated by colors. Although the probes for *28 and *6 had the same colors, their variants were clearly discriminated by probe Tm. The allelic frequencies of each genotype were 0.12 for *28, 0.19 for *6, 0.02 for *27, 0.0 for *29, and 0.005 for *7. We developed a multiplex PCR melting analysis method, which will be useful in molecular diagnostics and pharmacogenetic analyses in clinical laboratories.

Variant in C-terminal region of intestinal alkaline phosphatase associated with benign familial hyperphosphatasaemia.

BACKGROUND: A genetic diagnosis has been rarely performed in benign familial hyperphosphatasaemia, and molecular mechanism largely remains unclear. OBJECTIVES: We encountered a case with benign familial hyperphosphatasaemia of intestinal alkaline phosphatase (IAP). To elucidate the molecular mechanism, we performed ALPI gene sequencing and in vitro protein expression analysis. METHODS: ALPI gene was sequenced by long-range PCR and massively parallel sequencing. The soluble and membrane-bound ALP activities of the cultured cell line, transfected with the wild-type or variant-type ALPI gene were analysed by a glycosylphosphatidylinositol (GPI)-cleaving assay. RESULTS: We identified a deletion-insertion variant in the C-terminal end of the ALPI gene. This variant causes the attenuation of the hydrophobicity in GPI-anchor signal of IAP. An in vitro GPI-cleaving assay demonstrated that the membrane-bound IAP was greatly decreased, whereas the soluble IAP was increased, in the variant IAP. CONCLUSIONS: The C-terminal variant in ALPI causes the benign familial hyperphosphatasaemia of IAP by the attenuation of the membrane-binding capability.

Molecular Nodal Staging Using miRNA Expression in Lung Cancer Patients by Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration.

BACKGROUND: The limited negative predictive value of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has often been discussed. OBJECTIVE: The aim of this study was to identify a highly sensitive molecular biomarker for lymph node staging by EBUS-TBNA. METHODS: Five microRNAs (miRNAs) (miR-200a, miR-200b, miR-200c, miR-141, and let-7e) were selected as biomarker candidates for the detection of nodal metastasis in a miRNA expression analysis. After having established a cutoff level of expression for each marker to differentiate malignant from benign lymph nodes among surgically dissected lymph nodes, the cutoff level was applied to snap-frozen EBUS-TBNA samples. Archived formalin-fixed paraffin- embedded (FFPE) samples rebiopsied by EBUS-TBNA after induction chemoradiotherapy were also analyzed. RESULTS: The expression of all candidate miRNAs was significantly higher in metastatic lymph nodes than in benign ones (p < 0.05) among the surgical samples. miR-200c showed the highest diagnostic yield, with a sensitivity of 95.4% and a specificity of 100%. When the cutoff value for miR-200c was applied to the snap-frozen EBUS-TBNA samples, the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were 97.4, 81.8, 95.0, 90.0, and 94.0%, respectively. For restaging FFPE EBUS- TBNA samples, the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were 100, 60.0, 80.0, 100, and 84.6%, respectively. Among the restaged samples, 4 malignant lymph nodes were false negative by EBUS-TBNA, but they were accurately identified by miR-200c. CONCLUSIONS: miR-200c can be used as a highly sensitive molecular staging biomarker that will enhance nodal staging of lung cancer.

[Alternative Splicing Detection as Biomarker Candidates for Cancer Diagnosis and Treatment with Establishment of Clinical Biobank in Chiba University].

Alternative splicing is a fundamental process of gene regulation that contributes to protein diversity, a common phenomenon in the mammalian genome. Alternative splicing events not only happen in the normal gene regulation process, but are also closely related to certain diseases, including cancer. In this review, we briefly demonstrate the proof of concept (POC) of the relationship between alternative splicing and DNA damage, and describe the associations among alternative splicing and cancer pathogenesis, DNA damage, and gastrointestinal cancers. We discuss whether alternative splicing leads to genetic instability, which is considered to be a driving force for tumorigenesis. FUSE-binding protein (FBP) -interacting repressor (FIR) is a c-myc transcriptional suppressor. A splice variant of FIR that lacks exon 2 in the transcriptional repressor domain (FIRΔexon2), upregulates c-myc transcription by inactivating wild-type FIR. FIR+/- mice exhibited marked c-myc mRNA upregulation, particularly in the peripheral blood (PB), without any significant pathogenic phenotype. Because the single knockout of TP53 generates thymic lymphoma, FIR+/-TP53-/- mice developed T-cell type acute lymphocytic/lymphoblastic leukemia (T-ALL) with increased organ or bone marrow invasion and showed a poor prognosis. After describing the POC of alternative splicing of FIR in DNA damage and carcinogenesis, clinical application for cancer diagnosis and treatment by FIR/FIRΔexon2 was briefly summarized. Chiba University has prepared a biobank to support studies to develop biomarker detection, molecular diagnosis, and "Omics" research. In conclusion, alternative splicing of FIR, generating FIRΔexon2, potentially contributes to not only colorectal carcinogenesis, but also leukemogenesis, and a better understanding of the role and mechanism of alternative splicing in tumorigenesis may reveal new directions for cancer biomarker detection.

[Alternative Splicing Detection as a Biomarker for Cancer Diagnosis: A Novel Progressive Mechanism of Acute Lymphoblastic Leukemia with Alternative Splicing as a Biomarker Candidate].

Alternative splicing is an important mechanism that links to transcription and contributes to protein diversity. Disturbed alternative splicing is frequently observed in cancers, but its precise mechanism remains largely unknown. FUSE-binding protein (FBP) -interacting repressor (FIR) is a transcriptional repressor of the c-myc gene. Previous studies indicated that a splice variant of FIR, FIRΔexon2, that lacks exon2 in the transcriptional repressor domain, was increased in colorectal cancers, hepatocellular carcinomas, and leukemia cells. Furthermore, FIRΔexon2 activated c-myc transcription by disabling wild-type FIR as a dominant-negative form of FIR. Recently, somatic mutations of the SF3B1 (SAP155) gene, a subunit of the SF3B spliceosome complex, were found in myelodysplastic leukemia. In this study, FIR heterozygous knockout (FIR(+/-)) was established as a dominant-negative model of FIR in the C57BL/6 mouse. FIR(+/-) mice showed an increased c-myc mRNA expression level, particularly in peripheral blood, although FIR(+/-) mice had no apparent pathogenic phenotype. Therefore, an increased c-myc mRNA expression level alone is not enough for leukemogenesis. Nevertheless, FIR(+/-)TP53(-/-) mice generated acute T-cell lymphoblastic leukemia (T-ALL) with increased organ and/or bone marrow invasion. In conclusion, alternative splicing of FIR, generating FIRΔexon2, contributes to not only colorectal carcinogenesis but also leukemogenesis independent of the c-Myc activation pathway. Finally, we will discuss our hypothesis that FIRΔexon2 interferes with FBW7, that FIRΔexon2 inhibits PP1 in the EGFR pathway, and that FIR haploinsufficiency is potentially associated with protein expression through transcriptional and post-transcriptional mechanisms.

SAP155-mediated c-myc suppressor far-upstream element-binding protein-interacting repressor splicing variants are activated in colon cancer tissues.

The c-myc transcriptional suppressor, far-upstream element (FUSE)-binding protein (FBP)-interacting repressor (FIR), is alternatively spliced in colorectal cancer tissue (Matsushita et al., Cancer Res 2006). Recently, the knockdown of SAP155 pre-mRNA-splicing factor, a subunit of SF3b, was reported to disturb FIR pre-mRNA splicing and yield FIRΔexon2, an exon 2-spliced variant of FIR, which lacks c-myc repression activity. In the present study, novel splicing variants of FIR, Δ3 and Δ4, were also generated by SAP155 siRNA, and these variants were found to be activated in human colorectal cancer tissue. Furthermore, the expression levels of FIR variant mRNA were examined in the peripheral blood of colorectal cancer patients and healthy volunteers to assess its potency for tumor detection. As expected, circulating FIR variant mRNA in the peripheral blood of cancer patients were significantly overexpressed compared to that in healthy volunteers. In particular, the area under the receiving operating characteristic curve of FIR, FIRΔexon2 or FIRΔexon2/FIR, was greater than those of conventional carcinoembryonic antigen or carbohydrate antigen 19-9. In addition, FIRΔexon2 or FIR mRNA expression in the peripheral blood was significantly reduced after operative removal of colorectal tumors. Thus, circulating FIR and FIRΔexon2 mRNA are potential novel screening markers for colorectal cancer testing with conventional carcinoembryonic antigen and or carbohydrate antigen 19-9. Taken together, our results indicate that overexpression of FIR and its splicing variants in colorectal cancer directs feed-forward or addicted circuit c-myc transcriptional activation. Clinical implications for colorectal cancers of novel FIR splicing variants are also discussed in the present paper.

Combined proteomic analysis of liver tissue and serum in chronically alcohol-fed rats.

BACKGROUND: Proteomic approaches may provide new insights into pathological conditions associated with alcoholism. The aim of this study was to conduct a proteomic analysis of liver tissue and serum in chronically alcohol-fed rats using agarose 2-dimensional gel electrophoresis (2-DE) and 3-step serum proteome analysis. METHODS: A total of 12 rats were pair-fed nutritionally adequate liquid diet containing ethanol as 36% of the total energy or an isocaloric control diet for 2 months. Rat liver homogenates and cytosol fractions were subjected to agarose 2-DE. Serum samples were subjected to 3-step serum proteome analysis involving immunodepletion of abundant proteins followed by fractionation using reverse-phase high-performance liquid chromatography and 1-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Candidate proteins were digested with trypsin and identified using mass spectrometry. Observed differences in protein expression levels were confirmed using Western blotting. RESULTS: A total of 46 protein spots were found to be differentially expressed in the liver homogenates and cytosol fractions of alcohol-fed rats relative to pair-fed controls. The most notable change was down-regulation of a 29-kDa protein, which was subsequently identified as carbonic anhydrase III (CA III). Down-regulation of this protein in alcohol-fed rats was confirmed by Western blotting. The messenger RNA level of CA III was decreased as well. In rat serum, a total of 41 proteins were differentially expressed. Of these proteins, only betaine-homocysteine methyltransferase (BHMT) was also found to be differentially expressed in the liver. CONCLUSIONS: A combined proteomic analysis of liver tissue and serum in chronically alcohol-fed rats revealed that the expression of CA III is significantly down-regulated in the liver of alcohol-fed rats. Our results also showed that BHMT expression is up-regulated in both the liver and serum of alcohol-fed rats.

Pentanucleotide repeat-primed PCR for genetic diagnosis of spinocerebellar ataxia type 31.

Spinocerebellar ataxia type 31 (SCA31) is defined by the presence of an insertion mutation containing a TGGAA repeat within the intron of the brain-expressed, associated with NEDD4 (BEAN) gene. Detecting this mutation is conventionally done by southern blotting or DNA sequencing, but these methods are technically demanding and not easily implemented in clinical diagnosis. Here, we adapted repeat-primed PCR (RP-PCR) to develop a clinical genetic test for SCA31 using only the PCR process to detect the TGGAA repeat within the insertion mutation. Pentanucleotide RP-PCR and subsequent DNA fragment analysis demonstrated characteristic ladder peaks with a 5-bp periodicity, originating from the TGGAA repeat, in 100% of samples (n=14) from SCA31 patients in whom the presence of the TGGAA repeat had been verified by DNA sequencing. No peaks were observed in a normal control and two non-SCA31 patients, in whom the TGGAA repeat was absent. This method is valuable for genetic diagnosis of SCA31 in clinical practice.

Long-term follow-up of patients with hepatitis B e antigen negative chronic hepatitis B.

BACKGROUND AND AIM: After hepatitis B virus (HBV) e antigen (HBeAg) seroconversion, HBV-DNA continues to replicate, and HBeAg-negative patients still face the risk of liver disease progression. We investigated the predictive factors for alanine aminotransferase (ALT) elevation, antiviral drug use, and hepatocellular carcinoma (HCC) occurrence in HBeAg-negative patients. METHODS: Age, sex, ALT, platelet counts, HBV-DNA levels, genotype, antidiabetic drug use, body mass index, smoking, and alcohol consumption were analyzed for a total of 244 HBV carriers who were HBeAg-negative. RESULTS: Of 244 HBeAg-negative patients, 158 (64.8%) showed normal ALT levels at baseline. Multivariate Cox hazard regression analysis identified high HBV-DNA levels and high ALT at baseline as independent risk factors for ALT elevation in the patients with normal ALT at baseline. The threshold ALT and HBV-DNA levels were determined to be 31 IU/L and 5.3 log copies/mL, respectively. Seventeen (7.0%) patients used antiviral drugs. Multivariate Cox hazard regression analysis identified high HBV-DNA levels (threshold, 5.7 log copies/mL), the use of antidiabetic drugs, and daily alcohol consumption at baseline as an independent risk factor for the use of antiviral drugs in HBeAg-negative patients. In 10 patients (4.1%), HCC was detected, and a low platelet count (threshold, 10.0×10(4)/mm(3)) was associated with the occurrence of HCC. CONCLUSION: This study identified predictors of future active liver disease in HBeAg-negative patients, i.e. ALT elevation, unavoidable use of antiviral drugs, and occurrence of HCC.

Risk of hepatocellular carcinoma in patients with chronic hepatitis B virus infection.

OBJECTIVE: To determine the risk factors for the occurrence of hepatocellular carcinoma (HCC) in patients with hepatitis B virus (HBV) infection. MATERIAL AND METHODS: A total of 620 patients who tested positive for hepatitis B surface antigen and were referred to Chiba University Hospital between February 1985 and March 2008 were included in the study and the following characteristics were analyzed: age, gender, status of hepatitis B e antigen, alanine aminotransferase level, HBV DNA level, and number of platelets (PLTs). RESULTS: HCC was detected in 30 cases during the follow-up period (5.4 +/- 5.1 years). Multivariate analysis revealed that age > 40 years [compared with patients aged < 40 years; odds ratio (OR) = 4.28; 95% confidence interval (CI) = 1.68-10.9] and PLT level < 206,000/microl (compared with patients with a higher PLT level; OR = 8.50; 95% CI = 1.98-36.2) were predictive factors for HCC occurrence. In patients aged > 40 years, the HBV DNA level (compared with < 5.0 log copies/ml; OR = 4.22, 95% CI = 1.13-15.8) and PLT level (compared with patients with > 196,000/microl PLTs; OR = 15.6, 95% CI = 2.06-118.3) were predictive factors for HCC occurrence. CONCLUSIONS: Advanced age and low PLT level were risk factors for HCC occurrence in patients with HBV infection. In patients aged > 40 years, viral load was also a risk factor for HCC.

Pathogenesis of liver lesions in Theileria orientalis-inoculated cattle and severe combined immunodeficiency mice with bovine erythrocyte transfusion.

Theileria orientalis (T. orientalis) is a bovine protozoal disease similar to malaria in humans. Although the common outcome of malaria in humans and T. orientalis infection in cattle is hepatic disorder, the mechanisms of its development remain unknown. In this study, we investigated hepatocyte injury characterized by accumulation of macrophages with ingested erythrocytes in sinusoid and extramedullary hematopoiesis in cattle and mice experimentally infected with T. orientalis (T. orientalis-infected cattle and T. orientalis-infected mice). Vacuolization of hepatic cells was frequently observed in the vicinity of the aggregated macrophages in the liver sinusoids of T. orientalis-infected mice. A significant percentage of the macrophages accumulated in the liver sinusoids of the severely infected cattle and mice (14.6% and 24.2 to 53.2%, respectively) reacted positively with interleukin-1, interleukin-6 and TNF-α antibodies. Increase in the production of these cytokines was confirmed in T. orientalis-infected cattle and mice by real-time RT-PCR. These findings strongly suggest that increased cytokine production by the macrophages that have phagocytosed T. orientalis-infected erythrocytes causes hepatic disorder in T. orientalis-infected animals.

Differential gene analysis during the development of obliterative bronchiolitis in a murine orthotopic lung transplantation model: A comprehensive transcriptome-based analysis.

BACKGROUND: Obliterative bronchiolitis (OB) is a known issue during minor histocompatibility antigen (mHA) disparity during lung transplantation. This study evaluated gene expression in a murine orthotropic lung transplantation model using microarray analysis. METHODS: Left lungs from C57BL/10(H-2b) donor mice were transplanted into mHA-mismatched C57BL/6(H-2b) recipient mice. Three groups (OB, non-OB, and sham controls) were confirmed pathologically and analyzed. Gene expression changes in the lung grafts were determined by microarray and immunohistochemical staining, and genes were verified by quantitative PCR in the lungs and mediastinal lymph nodes (LNs). RESULTS: A total of 1343 genes were upregulated in the OB lungs compared to the sham group. Significant upregulation was observed for genes related to innate, e.g. Tlr2 and CCL3 and adaptive immunity, e.g. H2-ab1 and Il-21. Positive labeling for MHC class II antigen was observed in the bronchial epithelium of OB accompanied with B cells. We found increased Tlr2, Ccl3, H2-ab1, Il-21, Ighg3, Ifng, and Pdcd1 mRNA expression in the OB lung, and increased Il-21, Ighg3, and Pdcd1 expression in the OB LNs. CONCLUSIONS: Adaptive and innate immune reactions were involved in OB after lung transplantation, and genetic examination of related genes could be used for detection of OB.

[Clinical application of alternative splicing form of c-myc suppressor FUSE-binding protein-interacting repressor for cancer detection and treatment].

Development of useful biomarkers is pivotal for prediction of micro-metastasis, recurrence probability and/or prognosis of the patients. Recent studies have revealed that cancer-specific alternative splicing can be valuable for cancer cell detection. Among them, FUSE-binding protein-interacting repressor, FIR, has been reported to repress c-myc transcription and its exon2-spliced variant, FIRDelta(exon)2, is unable to repress c-myc by competing with authentic FIR in vivo and in vitro. Moreover FIRDelta(exon)2 was frequently discovered in human primary colorectal cancers, but not in the adjacent normal tissues, indicating its cancer-related expression. Thus, the expression level of FIRDelta(exon)2 mRNA in the colorectal cancer tissues as tumor marker candidates is examined. Further, to determine the interacting proteins, FIR-flag or FIRDelta(exon)2-flag stably expressing HeLa cells have been established by G418 selection and nuclear proteins were co immunoprecipitated with flag-conjugated magnetic beads. Those co-immunoprecipitated proteins with FIR or FIRDelta(exon)2 are candidates of tumor makers. In addition, substances that interfers FIR mRNA splicing should be anti-cancer drugs. Together, FIR splicing variant, FIRDelta(exon)2 mRNA or proteins and its interacting proteins are applicable for novel screening tumor markers in colorectal cancer detection.

Evaluation of analytical factors associated with targeted MEFV gene sequencing using long-range PCR/massively parallel sequencing of whole blood DNA for molecular diagnosis of Familial Mediterranean fever.

BACKGROUND: Long-range PCR (LR-PCR) is used to enrich the target regions of the genome. This study aimed to establish the pipeline of targeted gene sequencing using LR-PCR and massively parallel sequencing (MPS). METHODS: The 14-kb-long MEFV gene, including the entire coding exons, was selected as a target gene and amplified using LR-PCR. The evaluated analytical factors were as follows: LR-PCR conditions, three types of post-PCR cleanup methods, and two types of MPS library preparation methods. RESULTS: With regard to LR-PCR conditions, Tks Gflex DNA polymerase at 7-min (30-s/kb) annealing/extension with 100-ng genomic DNA input had the highest yield. Regarding post-PCR purification methods, the magnetic beads-based method had high recovery and purity. In the MPS library preparation methods, the ligation-based method had a higher base coverage in the target (94.58%), uniformity of base coverage (99.95%), and target bases with no strand bias (97.40%). The exonic variants determined by Sanger sequencing were detected by both ligation- and transposon-based methods. CONCLUSIONS: Various analytical factors were evaluated, and the pipeline of targeted gene sequencing using LR-PCR and MPS was established. These data can enable the optimization of targeted gene sequencing using LR-PCR and MPS in the clinical laboratory.

A simple method for sequencing the whole human mitochondrial genome directly from samples and its application to genetic testing.

Next-generation sequencing (NGS) is a revolutionary sequencing technology for analyzing genomes. However, preprocessing methods for mitochondrial DNA (mtDNA) sequencing remain complex, and it is required to develop an authenticated preprocessing method. Here, we developed a simple and easy preprocessing method based on isothermal rolling circle mtDNA amplification using commercially available reagents. Isothermal amplification of mtDNA was successfully performed using both nanoliter quantities of plasma directly and 25 ng of total DNA extracted from blood or tissue samples. Prior to mtDNA amplification, it was necessary to treat the extracted total DNA with Exonuclease V, but it was not required to treat plasma. The NGS libraries generated from the amplified mtDNA provided sequencing coverage of the entire human mitochondrial genome. Furthermore, the sequencing results successfully detected heteroplasmy in patient samples, with called mutations and variants matching those from previous, independent, Sanger sequencing analysis. Additionally, a novel single nucleotide variant was detected in a healthy volunteer. The successful analysis of mtDNA using very small samples from patients is likely to be valuable in clinical medicine, as it could reduce patient discomfort by reducing sampling-associated damage to tissues. Overall, the simple and convenient preprocessing method described herein may facilitate the future development of NGS-based clinical and forensic mtDNA tests.

Locked Nucleic Acid Technology for Highly Sensitive Detection of Somatic Mutations in Cancer.

The molecular diagnosis of the cancer mutational status is essential for modern clinical laboratory medicine. Mutations in EGFR, KRAS, BRAF, and PIK3CA genes are widely analyzed in solid tumors such as lung cancer, colorectal cancer, breast cancer, and melanoma. The allele-specific polymerase chain reaction, high-resolution melting, and Sanger sequencing are used for detecting and identifying gene mutations in many clinical laboratories. The locked nucleic acid (LNA) is a class of nucleic acid analogs that contain a methylene bridge connecting the 2' oxygen and 4' carbon in the ribose moiety. This methylene bridge locks the ribose group into a C3'-endo conformation. LNA, including an oligonucleotide, increases the thermal stability of hybrid strands. The use of LNA technology in molecular diagnostic methods improves the specificity and sensitivity of assays. This review describes routinely analyzed mutations and molecular diagnostic methods used in the clinical laboratory along with the performance improvement of mutational analysis with LNA.

Disturbed alternative splicing of FIR (PUF60) directed cyclin E overexpression in esophageal cancers.

Overexpression of alternative splicing of far upstream element binding protein 1 (FUBP1) interacting repressor (FIR; poly(U) binding splicing factor 60 [PUF60]) and cyclin E were detected in esophageal squamous cell carcinomas (ESCC). Accordingly, the expression of FBW7 was examined by which cyclin E is degraded as a substrate via the proteasome system. Expectedly, FBW7 expression was decreased significantly in ESCC. Conversely, c-myc gene transcriptional repressor FIR (alias PUF60; U2AF-related protein) and its alternative splicing variant form (FIRΔexon2) were overexpressed in ESCC. Further, anticancer drugs (cis-diaminedichloroplatinum/cisplatin [CDDP] or 5-fluorouracil [5-FU]) and knockdown of FIR by small interfering RNA (siRNA) increased cyclin E while knockdown of FIRΔexon2 by siRNA decreased cyclin E expression in ESCC cell lines (TE1, TE2, and T.Tn) or cervical SCC cells (HeLa cells). Especially, knockdown of SAP155 (SF3b1), a splicing factor required for proper alternative splicing of FIR pre-mRNA, decreased cyclin E. Therefore, disturbed alternative splicing of FIR generated FIR/FIRΔexon2 with cyclin E overexpression in esophageal cancers, indicating that SAP155 siRNA potentially rescued FBW7 function by reducing expression of FIR and/or FIRΔexon2. Remarkably, Three-dimensional structure analysis revealed the hypothetical inhibitory mechanism of FBW7 function by FIR/FIRΔexon2, a novel mechanism of cyclin E overexpression by FIR/FIRΔexon2-FBW7 interaction was discussed. Clinically, elevated FIR expression potentially is an indicator of the number of lymph metastases and anti-FIR/FIRΔexon2 antibodies in sera as cancer diagnosis, indicating chemical inhibitors of FIR/FIRΔexon2-FBW7 interaction could be potential candidate drugs for cancer therapy. In conclusion, elevated cyclin E expression was, in part, induced owing to potential FIR/FIRΔexon2-FBW7 interaction in ESCC.