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Results for “mutational profiling”

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PubMed2026

The Genomic Landscape of MYC-, MYCL-, and MYCN-Amplified Solid Tumors.

PURPOSE: MYC, MYCN, and MYCL amplifications are recurrent oncogenic events across solid tumors. Currently, no standardized selection biomarker is available to identify patients with MYC-dependent tumors. EXPERIMENTAL DESIGN: We analyzed copy-number alterations of MYC family genes and their features in more than 68,000 tumor-normal paired samples from pediatric and adult patients sequenced with MSK-IMPACT (Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets) and annotated with FACETS (Fraction and Allele-Specific Copy Number Estimates from Tumor Sequencing). The relationship between amplification features and MYC mRNA expression levels were evaluated in more than 10,000 samples from The Cancer Genome Atlas (TCGA). RESULTS: Across MSK Cancer Center samples, MYC amplifications were most common, found in 2,949 samples compared with 310 in MYCL and 217 in MYCN. Although MYCN and MYCL amplifications were predominantly focal (<10 Mb, 79% and 93%, respectively), MYC amplifications were frequently broader (>10 Mb, 62%). Although most tumor types showed similar features between broad and focal amplifications of MYC, in select cancer types, we identified differing co-occurrence and mutual exclusivity patterns with other disease-specific drivers. Furthermore, although MYC-amplified TCGA samples showed higher mRNA expression than wild-type ones, the focality of MYC amplification was seen to have limited influence on expression levels. CONCLUSIONS: Our results suggest that MYC dependency likely depends on many factors, including, but not limited to, total copy number of the detected amplification, lineage-specific factors, concomitant presence or absence of additional oncogenic alterations, and in some cases amplification focality.

Humans↗

PubMed2025

Whole-exome sequencing uncovers the genetic basis of hereditary concomitant exotropia in ten Chinese pedigrees.

PURPOSE: To explore possible pathogenic genes for concomitant exotropia using whole-exome sequencing. METHODS: In this study, 47 individuals from 10 concomitant exotropia (including intermittent exotropia and constant exotropia) pedigrees were enrolled. Whole-exome sequencing was used to screen mutational profiles in 25 affected individuals and 10 unaffected individuals. Sanger sequencing and in silico analysis were performed for all participants. Two target genes were used to capture the sequences of 220 sporadic samples. RESULTS: All 10 concomitant exotropia pedigrees presented autosomal dominant inheritance with childhood onset (3.35 ± 1.51 years old). Eleven different missense variants were identified among seven potential pathogenic genes (COL4A2, SYNE1, LOXHD1, AUTS2, GTDC2, HERC2 and CDH3) that cosegregated with pedigree members. All variants were predicted to be deleterious and had low frequencies in the general population. Distinct variants of COL4A2 were present in three pedigrees, and distinct variants of SYNE1 were present in two pedigrees. Fifteen variants in AUTS2 and four variants in GTDC2 were identified in 220 patients with sporadic concomitant exotropia using a target-capture sequencing approach. CONCLUSION: This is the first study to explore the genetic mechanism of concomitant exotropia and identify seven associated genes (COL4A2, SYNE1, LOXHD1, AUTS2, GTDC2, HERC2 and CDH3) that may be candidate genes causing concomitant exotropia. More samples and in-depth studies are needed to verify these findings.

Adult↗

PubMed2006

Advancement in characterization of genomic alterations for improved diagnosis, treatment and prognostics in cancer.

Most human cancers are characterized by genetic instabilities. These instabilities manifest themselves as a series of genetic alterations, including discrete mutations and chromosomal aberrations. With the human genome deciphered, high-throughput technologies are rapidly advancing the field to generate genome-wide gene expression and mutation profiles that are highly correlative of biologic and disease phenotypes. While recent advancement in comprehensive genomic characterization presents an unprecedented opportunity for advancing the treatment of cancer, there are still many challenges that need to be overcome before we can fully utilize genomic markers and targets for cancer prediction, diagnostics, treatment and prognostics. This review describes recent advances in comprehensive genomic characterization at the DNA level, and considers some of the challenges that remain for defining the precise genomic portrait of tumors. Potential solutions that may help overcome these challenges are also offered.

Animals↗

PubMed2026

Mitochondria related gene signature serves as prognosis prediction and risk stratification of cholangiocarcinoma.

BACKGROUND: Cholangiocarcinoma (CHOL) is a highly aggressive biliary malignancy with poor clinical outcomes and limited effective prognostic biomarkers. Mitochondrial dysfunction participates in multiple oncological processes of CHOL, yet the prognostic roles of mitochondria‑related genes (MRGs) remain poorly understood. This study aimed to characterize MRGs expression in CHOL and develop a molecular prognostic model for predicting patient survival and guiding clinical management. METHODS: RNA sequencing (RNA-seq) and clinical data of CHOL were obtained from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) (GSE89748) databases. Differentially expressed MRGs were identified, and 10 machine learning algorithms were used to construct prognostic models. The optimal model (highest average C-index) was selected to establish a mitochondria-related risk score (MRRS), which was validated internally and externally. A nomogram integrating clinical factors and MRRS was developed, and biological mechanisms were explored via functional and immune analyses. RESULTS: A 3-MRG (MAP3K1, MRPL18, PYGB) prognostic signature was constructed, stratifying patients into high- and low-risk groups with significantly different overall survival. The model showed high predictive accuracy, with an area under the curve (AUC) up to 0.845, and MRRS was an independent prognostic factor. The signature was associated with mitochondrial pathways, and the high-risk group had distinct immune infiltration and mutation profiles. CONCLUSIONS: A validated MRG prognostic model effectively stratifies CHOL patients and has potential clinical value for prognosis prediction. Further validation in larger cohorts is needed to confirm its applicability.

Cholangiocarcinoma (CHOL)↗

PubMed1998

Saquinavir. Clinical pharmacology and efficacy.

Saquinavir is an HIV protease inhibitor with no, or limited, effect on the activity of other structurally related human aspartic proteinases. As with other HIV protease inhibitors, saquinavir inhibits the cleavage of the gag-pol protein substrate leading to the release of structurally defective and functionally inactive viral particles. It is active on both HIV-1 and HIV-2, and also has activity on chronically infected cells and HIV strains resistant to reverse transcriptase inhibitors. Synergy of action has been observed with other antiretroviral drugs. Saquinavir is characterised by a low bioavailability which is further reduced in the fasting state. Metabolism is mainly hepatic through cytochrome P450 (CYP) 3A4, but intestinal metabolism through the same system has also been reported. To achieve higher drug plasma concentrations and increase the antiviral effect, a new formulation of saquinavir with a higher bioavailability has recently been introduced. Higher plasma drug concentrations may also be obtained by combining the drug with CYP blockers, such as ritonavir or ketoconazole. Because of its metabolic interference with the CYP system, saquinavir cannot be coadministered with astemizole, terfenadine or cisapride. Rifampicin (rifampin) is also contraindicated because coadministration can lead to decreases in saquinavir concentrations. Interactions have also been reported with other drugs metabolised through the same system, including non-nucleoside reverse transcriptase inhibitors and HIV protease inhibitors. Resistance has been observed after both in vitro and in vivo drug exposure, with a relatively specific mutation profile compared with other protease inhibitors. Saquinavir is generally well tolerated, with mild gastrointestinal symptoms representing the most commonly observed adverse effects. Although characterized by low bioavailability, in phase III trials saquinavir has been shown to have clinical efficacy in terms of survival and progression rate. As with the other protease inhibitors, saquinavir should be used in combination with other antiretroviral drugs. Current therapeutic guidelines, however, recommend the selection of an initial treatment regimen with other protease inhibitors with higher in vivo activity in terms of RNA and CD4 response. The results of ongoing studies will clarify to what extent a new saquinavir formulation, recently introduced, is superior to the previous one in terms of antiviral activity and to provide comparisons with other protease inhibitors. Further studies are also needed to define the best place of saquinavir within treatment strategies based on protease inhibitors, particularly in respect to the optimal sequence for its use with other protease inhibitors, and the dynamics of cross-resistance and its role within regimens based on the combination of protease inhibitors.

Anti-HIV Agents↗

PubMed2001

The COOH terminus of p18INK4C distinguishes function from p16INK4A.

The INK4 family of proteins consists of four members which can block progression from the G(1)-to-S phase of the cell cycle by inhibiting the activity of cyclin dependent kinases (cdks) 4 and 6. Although the gene encoding p16(INK4a) is commonly inactivated in human tumors, p18(INK4c) is rarely altered. We show here that overexpression of p18(INK4c) does not block cell cycle progression in a T-cell acute lymphocytic leukemia cell line (CEM) sensitive to p16(INK4a)-mediated G(1) arrest. A chimera consisting of the kinase-binding region of p16(INK4a) fused to the COOH terminus of p18(INK4c) is active in all known biochemical assays for INK4 function, but it does not arrest CEM cells. These data imply a novel level of p18(INK4c) regulation mediated through the COOH terminus and suggest that functional differences might underlie the distinct mutational profiles observed for p16(INK4a) and p18(INK4c) in tumors.

Amino Acid Sequence↗

PubMed2002

[Update on malignant hemopathies].

The beginning of this century was marked, in our specialty as in other, by two revolutions: the routine use of molecular biology tools for a better prognosis of the disease (flt3 receptor duplication in AML, mutational profile of Ig genes in CLL, gene expression profile with ARN chips in aggressive lymphomas.), and the discovery of "intelligent" molecules, targeting the tumoral cell. In this category, the most appealing is the STI571 (Gleevec , Novartis), targeting the molecular abnormality of the cells expressing bcr-abl protein: CML, ALL Ph1(+). Other molecules targeting signal transduction proteins (ras farnesylation inhibitors for example) are already in clinical trials. The increasing therapeutic use of monoclonal antibodies is also to be cited, with a special mention concerning the rituximab, used in several B lymphoid pathologies, from lymphoma to autoimmune diseases. His very good tolerance permits his use in ambulatory patients, and his combination with chemotherapy or his linkage with radioactive elements render this molecule indispensable. The other side of these molecules is their incredibly high cost, explaining the uncontrolled expenses in 2001 of hospitals hosting hematology as well as oncology activities.

Acute Disease↗

PubMed2002

Comparison of accumulated allele loss between primary tumor and lymph node metastasis in stage II non-small cell lung carcinoma: implications for the timing of lymph node metastasis and prognostic value.

Although the Tumor-Node-Metastasis staging of non-small cell lung carcinoma (NSCLC) is the most effective predictor of survival, the clinical outcome of patients at each stage is variable on an individual case basis. We tested the value of incorporating information about the tumor heterogeneity of NSCLC into microsatellite allelotyping in a cohort of 48 node-positive stage II patients (T1N1M0 and T2N1M0). Microsatellite allelotyping involved microdissection of the invasive component of primary tumor and lymph node metastasis at multiple target sites followed by loss of heterozygosity (LOH) analysis at specific regions on chromosomes 1p, 3p, 5q, 7q, 8q, 9p, 10q, 17p, and 18q using 16 markers. All microsatellites manifested LOH ranging from 44 to 76% in primary tumor and showed various degree of heterogeneity between primary tumor and lymph node metastasis. LOH on 3p and 5q in the lymph node metastases was associated significantly with shortened survival of the patients (P = 0.033 and 0.004, respectively), whereas no single LOH in the primary tumors showed association with prognosis. For the analysis of the accumulated load of allele loss, fractional allele loss (FAL) was calculated for each sample. The maximal FAL of lymph node metastasis was significantly lower than that of primary tumor (P = 0.0015), possibly reflecting the early lymphatic spread. High maximal FAL of lymph node metastasis was significantly correlated with an adverse outcome (P = 0.012), whereas maximal FAL of primary tumor did not show any prognostic significance (P = 0.552). A composite mutational profile for each patient based on the allelotyping of the primary tumor and lymph node deposits may make a significant contribution to a more accurate prognosis of stage II NSCLC.

Aged↗

PubMed2002

The effects of antiretroviral dose modification on the re-emergence of HIV-1 wild-type strains.

Four human immunodeficiency virus type 1 (HIV-1) treatment-naïve Thai patients began antiretrovival therapy with a triple drug regimen -zidovudine plus lamivudine plus indinavir; this regimen was modified at week 20 of therapy because of drug toxicity. The virus in all patients was suppressed to lower than 400 copies/ml while they were taking the triple antiretroviral drug regimen. However, suppression was lost after changing the antiretroviral regimen. A comparison of HIV-1 DNA sequences taken from the baseline (day 0) and week 24 showed no significant overgrowth in HIV-1 drug-resistant strains. There was no difference in the protease and reverse transcriptase (RT) mutation profiles. Resistant variants did not emerge, even after sub-therapeutic levels of antiretroviral drugs had been introduced to these patients for 4 weeks. These findings may have clinical implications for long-term treatment strategies.

Anti-HIV Agents↗

PubMed2005

Allelic loss in parathyroid neoplasia can help characterize malignancy.

Parathyroid carcinoma can be difficult to diagnose, and the final pathologic diagnosis relies on clinicopathologic correlation. Clinical features of malignancy include high preoperative calcium levels and an intraoperative impression that the gland is adherent to local structures. Histologic features of malignancy include increased mitoses, vascular invasion, and broad bands of fibrosis. This study used molecular genotyping to assess parathyroid neoplasia for loss of heterozygosity across a panel of known tumor suppressor genes that have been previously identified as being important in the pathogenesis of parathyroid diseases. Parathyroid adenomas, hyperplasia, and carcinomas were included in the study, and a fractional allelic loss was calculated for each lesion. Losses of 1q25, 7q13.3, 10q23, 13q14.3, and 11p15.5 were particularly prevalent. In addition, almost all adenomas and carcinomas had loss of the markers for 1p. The benign parathyroid diseases (adenomas and hyperplasia) had low mean fractional allelic loss (11% and 15%, respectively). The parathyroid carcinomas, in contrast, showed high mean fractional allelic loss (63%). This difference in the mutational profile suggests that this type of assay may be useful as an adjunctive diagnostic test in cases of parathyroid neoplasia.

Adenoma↗

PubMed2006

Large- and small-molecule inhibitors of transforming growth factor-beta signaling.

A variety of drugs have been developed to inhibit transforming growth factor (TGF)beta signaling. These drugs have been designed to block TGFbeta synthesis, ligand/receptor binding or receptor kinase signaling. Preclinical studies using TGFbeta inhibitors have demonstrated efficacy in reducing metastasis and have shown improvements in cytotoxic drug delivery. Results of phase I/II clinical trials of TGFbeta inhibitors in patients with glioblastoma suggest improved survival rates compared with conventional chemotherapy. The predominant cellular target, whether cancer or stromal cell, immune cell or angiogenesis, may differ between tumor types. Different individuals may show variable responses to drug therapy dependent on both germline genetic variation and the somatic mutation profile of the tumor. A deeper understanding of these issues will assist in targeting the right patients for such therapy, and in limiting unwanted side effects.

Animals↗

PubMed1996

[Profile of p53 mutations and abnormal expression of P53 protein in 2 forms of esophageal cancer].

AIMS AND METHODS: p53 tumor suppressor gene is involved in the development of esophageal cancer. However, its role is not precisely defined in the two types of cancer, squamous cell carcinoma and adenocarcinoma developed in Barrett's esophagus. The aim of this work was to compare the frequency and type of mutation of the p53 gene and the expression of the p53 protein in a series of 21 squamous cell carcinomas and 27 adenocarcinomas of the esophagus in a single institution. p53 protein accumulation was assessed by immunohistochemistry with the monoclonal antibody PAb 1801. The mutations of exons 5 to 8 of p53 gene were detected by denaturating gradient gel electrophoresis, and sequenced. RESULTS: A mutation of the p53 gene and/or an accumulation of the p53 protein were found in 85% of squamous cell carcinomas and 92% of adenocarcinomas, respectively. The profile of mutations differed with the type of tumor; large predominance of transitions on CpG dinucleotides in adenocarcinomas suggesting an endogenous mechanism, high percentage of transversions in squamous cell carcinomas suggesting a direct effect of carcinogens present in tobacco and alcohol. CONCLUSION: Mutation of the p53 gene is a very frequent event in the two types of esophageal cancer. The mechanism responsible for these mutations is different in squamous cell carcinomas and adenocarcinomas developed in Barrett's esophagus.

Adenocarcinoma↗

PubMed1995

Dose-related changes in the profile of ras mutations in chemically induced CD-1 mouse liver tumors.

We investigated the role of dosing regimen on ras mutations in chemically induced CD-1 mouse liver tumors. The spectra of ras gene mutations in liver tumors that were induced by 15 daily i.p. injections of 7,12-dimethylbenz[a]anthracene (DMBA), 4-aminoazobenzene (AAB), N-hydroxy-2-acetylaminofluorene (N-OH-AAF) or N-nitrosodiethylamine (DEN) were compared to those previously obtained for tumors induced by a single but higher dose of each carcinogen. The principal assay used was a direct tumor analysis involving sequencing of polymerase chain reaction (PCR)-amplified tumor DNA; additional mutations that were present in only a small fraction of tumor cells were detected using a transfection assay or a PCR-engineered restriction fragment length polymorphism method. Spontaneous liver tumors had a relatively low frequency of ras mutations, all found in Ha-ras codon 61, and most of these mutations were present in only a small fraction of tumor cells. With the exception of multiple-dose DEN, each group of single- and multiple-dose carcinogen-induced tumors exhibited a higher frequency of ras mutations compared with spontaneous tumors. For AAB, N-OH-AAF and DEN, the dosing regimen was found to affect significantly the profile of ras mutations. For each of these carcinogens, the multiple-dose tumor group (versus single-dose group) had fewer Ki-ras and N-ras mutations and more tumors in which the Ha-ras codon 61 (C-->A) mutation was present in a large fraction of cells. Our results demonstrate that the dosing procedure can materially affect the pattern of ras gene mutation in mouse liver tumors.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed2006

Modeling tumor predisposing FH mutations in yeast: effects on fumarase activity, growth phenotype and gene expression profile.

Heterozygous mutations in the fumarase (FH) gene cause the tumor predisposition syndrome hereditary leiomyomatosis and renal cell cancer (MIM 605839). While most families segregate a benign phenotype of multiple leiomyomas, others display a phenotype with early-onset renal cancer and leiomyosarcoma. Modifier genes may play a role in this, but an alternative explanation is simple genotype-phenotype association. FH mutations predisposing to cancer appear to be truncating or in fully conserved amino acids, suggesting that mutations severely affecting FH activity might predispose to malignancy. In the present study, we analyzed 2 conserved fumarase mutations in yeast. H153R has been described in 3 cancer predisposition families; whereas all 3 reported K187R families have displayed the benign phenotype. Examining H153R and K187R should clarify whether cancer-related FH mutations differ from their benign phenotype-associated counterparts. Yeast strains containing the 2 mutations, and knockout and wild type (WT) references, were created and the growth phenotypes studied on selected carbon sources to assess mitochondrial function. Additionally, Fum1 protein production and activity were measured, and the strains were subjected to transcriptional profiling. On nonfermentable lactate medium, the fumarase knockout strains did not grow, whereas the mutants showed no differences, as compared to WT yeast. Although both mutant strains produced fumarase, a considerable decrease in enzyme activity was seen in mutants with respect to WT. Transcription of the majority of Krebs cycle enzymes was downregulated in response to mutations in fumarase. In conclusion, both mutants displayed some, albeit greatly reduced, fumarase activity. This activity was sufficient to support normal growth on nonfermentable carbon source, unlike the deletion phenotype, demonstrating the significance of the residual activity. The findings support the hypothesis that modifier gene(s), rather than phenotype-genotype effects, display a major role in determining tumor phenotypes in families segregating FH mutations.

Cell Division↗

PubMed2026

Comprehensive genomic profiling and tumor mutational burden in parathyroid carcinoma: a nationwide real-world study from Japan.

PURPOSE: Parathyroid carcinoma (PC) is an extremely rare endocrine malignancy with limited treatment options for unresectable or recurrent cases. With the increasing use of comprehensive genomic profiling (CGP), treatment based on genomic findings is becoming more common. However, the frequency and clinical significance of elevated tumor mutational burden (TMB) in PC remain unclear because previous studies have been limited by small sample sizes. METHODS: We retrospectively analyzed genomic and clinical data of patients with PC registered in the Center for Cancer Genomics and Advanced Therapeutics database in Japan between June 2019 and March 2025. TMB values were obtained as reported by each CGP assay. TMB-H was defined as TMB ≥ 10 mut/Mb for descriptive analyses. We also assessed genomic alterations, microsatellite instability (MSI) status, and clinicogenomic characteristics. RESULTS: Twenty-five patients with PC were included. The median assay-reported TMB was 4.0 mut/Mb (range, 0-35). Seven tumors (28.0%) had assay-reported TMB values of ≥ 10 mut/Mb, including three (12.0%) with TMB ≥ 20 mut/Mb. The most frequently altered genes were CDC73 (40%), TP53 (32%), and MEN1 (24%). No co-alterations were observed between CDC73 and MEN1 or between CDC73 and TP53. One tumor was MSI-high and was included in the TMB-H group. POLE alterations were detected in three cases, including two tumors in the TMB-H group. CONCLUSION: This nationwide, real-world study demonstrated that a subset of PCs showed elevated assay-reported TMB values and genomic features potentially related to abnormalities in DNA replication or repair pathways. These findings support the clinical relevance of comprehensive genomic profiling in identifying the molecular heterogeneity and potential therapeutic opportunities for this rare malignancy.

Humans↗

PubMed2003

[Analysis of p53 mutational spectra of esophageal squamous cell carcinomas from Linzhou, comparison with esophageal and other cancers from other areas].

OBJECTIVE: To study the etiological clues involved (in esophageal cancer in Linzhou, Henan, a high-incidence area for esophageal cancer) by analyzing p53 mutational spectrum from esophageal precancerous and cancerous lesions. METHODS: Using bolt bioinformatic and Monte Carlo methods to analyze p53 mutation spectra from "The IARC Database of Somatic p53 Mutations in Human Tumors and Cell Lines", "p53 Database at Institute Curic" and to establish a local database based on these data using the FileMark Pro 3.0 software to allow fast and off-line analysis on a PC from the authors' laboratory. RESULTS: We found that esophageal squamous cell carcinomas from Linzhou had a lower prevalence of base substitutions associated with strand bias than those from other areas (32.8% vs 39.8%). However, a higher prevalence of G:C-->A:T transitions at CpG site (29.6% vs16.4%) was found. Esophageal squamous cell carcinomas from Linzhou displayed a distinctive profile of mutation hotspots, including codons 273 (covers 11.3% of all missense mutations), 175 (9.7%), 158 (9.7%), 159 (6.5%) and 282 (6.5%), all of which were at the CpG site. Statistical analysis showed that the p53 mutation profiles between esophageal squamous cell carcinomas from Linzhou and those from other areas were different (P = 0.02). The p53 mutation profiles of esophageal squamous cell carcinomas from Linzhou and from other areas were also different from cancer of the head and neck. CONCLUSION: Data showed that the p53 mutational spectrum of esophageal squamous cell carcinomas from Linzhou baring the characteristics of those caused both by endogenous and exogenous mutagenic agents, suggesting the potential involvement of chronic inflammation, unique dietary habits and carcinogen exposure in the pathogenesis of esophageal squamous cell carcinoma in Linzhou.

Carcinogens, Environmental↗

PubMed2005

Molecular classification of papillary thyroid carcinoma: distinct BRAF, RAS, and RET/PTC mutation-specific gene expression profiles discovered by DNA microarray analysis.

Thyroid cancer poses a significant clinical challenge, and our understanding of its pathogenesis is incomplete. To gain insight into the pathogenesis of papillary thyroid carcinoma, transcriptional profiles of four normal thyroids and 51 papillary carcinomas (PCs) were generated using DNA microarrays. The tumors were genotyped for their common activating mutations: BRAF V600E point mutation, RET/PTC1 and 3 rearrangement and point mutations of KRAS, HRAS and NRAS. Principal component analysis based on the entire expression data set separated the PCs into three groups that were found to reflect tumor morphology and mutational status. By combining expression profiles with mutational status, we defined distinct expression profiles for the BRAF, RET/PTC and RAS mutation groups. Using small numbers of genes, a simple classifier was able to classify correctly the mutational status of all 40 tumors with known mutations. One tumor without a detectable mutation was predicted by the classifier to have a RET/PTC rearrangement and was shown to contain one by fluorescence in situ hybridization analysis. Among the mutation-specific expression signatures were genes whose differential expression was a direct consequence of the mutation, as well as genes involved in a variety of biological processes including immune response and signal transduction. Expression of one mutation-specific differentially expressed gene, TPO, was validated at the protein level using immunohistochemistry and tissue arrays containing an independent set of tumors. The results demonstrate that mutational status is the primary determinant of gene expression variation within these tumors, a finding that may have clinical and diagnostic significance and predicts success for therapies designed to prevent the consequences of these mutations.

Base Sequence↗

PubMed2005

Mitochondrial D-loop mutations and deletion profiles of cancerous and noncancerous liver tissue in hepatitis B virus-infected liver.

The largest single underlying cause of hepatocellular carcinoma (HCC) worldwide is hepatitis B virus (HBV) infection. Hepatitis B virus increases cellular oxidative stress and the development of HCC occurs after a long latency period. The study was carried out to determine whether mitochondrial DNA abnormalities were associated with HCC in individuals with HBV. The frequency of mutation and deletion of specific areas of the mitochondrial genome in tumour and matched normal tissue of patients with HBV infection was investigated in the current study. The percentage of control subjects harbouring D-loop mutations was 11%, which was significantly lower than that observed in both the noncancerous (49%, P=0.033) and tumour tissue (59%, P=0.014) of patients with HCC. In contrast, the number of cases in which the common 4977 bp deletion of the mitochondrial genome was detected was significantly greater in control liver and noncancerous liver tissue of subjects with HCC (100 and 95%, respectively) than in cancerous liver tissue (28%, P<0.001). These observations suggest that the inflammatory process contributes to the rate of mitochondrial mutations. However, the lower frequency of the large deletion in cancerous tissue suggests that there is selection against either mitochondria, which harbour large deletions, or against cells that contain these mitochondria during hepatocarcinogenesis.

Adult↗