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Molecular diagnostic methods in the diagnosis and follow-up of well-differentiated thyroid carcinoma.

Thyroid cancers are the most common endocrine malignancies and are being diagnosed with increased frequency in modern clinical practice. Among other diagnostic modalities, fine-needle aspiration (FNA) biopsy of clinically suspicious thyroid nodules is becoming increasingly popular. Preliminary investigations have suggested that molecular diagnostic assays using tumor-specific markers may improve the sensitivity and accuracy of FNA and so may be expected to reduce the frequency of open surgical procedures by identifying those patients with demonstrably benign lesions who do not require definitive surgical excision of their lesions for diagnosis. At the same time, thyroid-specific mRNA assays (especially thyroglobulin mRNA testing) have been used by investigators in the postoperative follow-up of patients with thyroid cancer as a potential means of detecting tumor recurrence in the peripheral blood. Although these studies have not all reported unqualified successes--indeed, some problems based on both technical and biologic limitations have been identified-these assays still hold out the possibility that potentially important new advances in the management of patients with well-differentiated thyroid cancer may be offered by these and other molecular diagnostic methods.

Biomarkers, Tumor↗

[Perspectives for molecular diagnostics exemplified by urothelial bladder carcinoma].

The rapidly growing knowledge of molecular mechanisms will change the daily routine of clinicians in the near future. Regarding urothelial bladder carcinoma, one may expect that molecular diagnostics will identify patients susceptible to disease development by screening their genotype. Furthermore, in addition to histopathologic findings, prognostic markers will be used for disease management. In an ongoing multicenter trial, the decision on whether or not to treat patients with adjuvant chemotherapy after cystectomy is based on their p53 status. In the near future, cytostatic medications are expected to be chosen according to genetic profiles of the tumor or patient. New medications, which target tumor-specific alterations of cell-signaling cascades in bladder or other cancers, prominently inhibitors of the ERBB membrane receptor family, are currently under clinical investigation and will undoubtedly form an important part of therapeutic oncologic regimens. In conclusion, evaluation of gene profiles of tumors and patients will gain importance for clinicians.

Cell Transformation, Neoplastic↗

Molecular diagnostics of catecholaminergic polymorphic ventricular tachycardia using denaturing high-performance liquid chromatography and sequencing.

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an arrhythmogenic disease characterized by adrenergic-induced arrhythmias in the form of bidirectional and PVT. CPVT is a distinct clinical entity associated with a high mortality rate of up to 50% by the age of 30 yr. Recently, the molecular diagnostics of this disease have become increasingly important because underlying mutations can be found in more than 60% of the identified CPVT patients. Along with the fact that treatment with beta-blockers has a favorable outcome in CPVT patients, and given the risk of sudden death, the identification of causative mutations in CPVT is important because it can greatly augment early diagnosis and subsequent preventive strategies. In this chapter, we describe the molecular diagnostics, as performed in our lab, of the three genes known to be involved in CPVT, the cardiac ryanodine receptor gene, the cardiac calsequestrin gene, and the inwardly rectifying potassium channel KCNJ2.

Base Sequence↗

Molecular diagnostics for polychlorinated biphenyl degradation in contaminated soils.

Molecular diagnostic methods using DNA hybridization with specific gene probes are being developed for the monitoring of microbial populations capable of polychlorinated biphenyl (PCB) degradation in contaminated soils. Evaluation of composite samples from contaminated electrical substation soil by gas chromatography (GC) indicated that the PCBs present in the soil (approximately 200 ppm) resulted from contamination with Aroclor 1248. The PCBs have been weathered or degraded so that the lower molecular weight PCB congeners are no longer present. Microbiological and molecular site characterizations are in progress to determine the abundance of PCB degradative organisms and catabolic genes present. Cloned DNA fragments for the bphC gene (2,3-dihydroxybiphenyl dioxygenase) from the biphenyl/chlorobiphenyl degradative pathways of different organisms were used as gene probes to identify indigenous microorganisms with bphC gene sequences. In colony hybridization experiments, positive signals with the pDA251 gene probe were detected in cultures from both contaminated and uncontaminated soils. The degradative abilities of indigenous microorganisms and an added PCB-degradative bacterial strain were also monitored with [14C]4-chlorobiphenyl mineralization assays and gas chromatography of PCB residues extracted from the soils. Enrichment of the contaminated soil with biphenyl and chlorobiphenyls did not stimulate the indigenous microorganisms to degrade the soil PCB. Nevertheless, enrichment of the contaminated soil with biphenyl and chlorobiphenyl and addition of the PCB-degrading strain Alcaligenes eutrophus GG4202 did result in additional degradation of the soil PCB. The results obtained from these experiments should assist in developing and monitoring a remediation plan for these PCB-contaminated soils.

Biodegradation, Environmental↗

Haplotype analysis improves molecular diagnostics of autosomal recessive polycystic kidney disease.

BACKGROUND: Autosomal recessive polycystic kidney disease (ARPKD) is characterized by wide phenotypic variability, ranging from in utero detection with enlarged, echogenic kidneys to an adult presentation with congenital hepatic fibrosis. The ARPKD gene, PKHD1 , covers about 470 kb of DNA (67 exons), and mutation studies have found marked allelic heterogeneity with a high level of novel missense changes and neutral polymorphisms. To improve the prospects for molecular diagnostics and to study the origin of some relatively common mutations, the authors have developed a strategy for improved ARPKD haplotyping. METHODS: A protocol of multiplex PCR and fluorescence genotyping in a single capillary has been developed to assay 7 highly informative simple sequence repeat (SSR) markers that are intragenic or closely flanking PKHD1. RESULTS: Examples in which haplotype analysis, used in combination with mutation screening, improved the utility of molecular diagnostics, especially in families in which just a single PKHD1 mutation has been identified, are illustrated. The new markers also allow screening for larger DNA deletions, detecting unknown consanguinity and exploring the disease mechanism. Analysis of 8 recurring mutations has shown likely common haplotypes for each, and the divergence from the ancestral haplotype, by recombination, can be used to trace the history of the mutation. The common mutation, T36M, was found to have a single European origin, about 1,225 years ago. CONCLUSION: Improved haplotype analysis of ARPKD complements mutation-based diagnostics and helps trace the history of common PKHD1 mutations.

3' Flanking Region↗

Role of molecular diagnostic testing in familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer families.

PURPOSE: Genetic tests are available for familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer. The goal of this review was to develop an algorithm for application of molecular diagnostic techniques to the management of hereditary colorectal carcinoma and to familiarize the clinician with the vocabulary of molecular genetic testing for hereditary colorectal carcinoma. METHODS: Studies examining the clinical use of genetic testing for hereditary colorectal carcinoma syndromes are evaluated. Recent advances in molecular genetic technology are reviewed, and clinical management as practiced here and elsewhere is outlined. RESULTS: This review is a guide to the most reliable molecular diagnostic techniques. Three key questions are answered: who, when, and how to test. CONCLUSIONS: When integrated with existing testing protocols for colorectal carcinoma and when applied with appropriate caveats, particularly regarding interpretation of negative results, genetic testing can result in improved management of patients and families.

Adenomatous Polyposis Coli↗

[Molecular diagnostic techniques of Wolbachia].

Wolbachia is a common and widespread group of bacteria found in reproductive tissues of arthropods. These bacteria are transmitted through the cytoplasm of eggs and have evolved various mechanisms for manipulating reproduction of their hosts. Because of important relationship with some major biological issues and implication of biological control and genetic engineering, the study of Wolbachia has under gone an explosive growth in recent years. A tremendous progress has been made based on the advancing molecular diagnostic technique of Wolbachia. In this paper, those molecular diagnostic techniques are detailed and it is aimed to be the primer for the research of Wolbachia in China.

English Abstract↗

2nd International Symposium on Molecular Diagnostics and Skin Gene Therapy.

The 2nd International Symposium on Molecular Diagnostics and Skin Gene Therapy was held on a beautiful spring weekend at one of the youngest universities in the world, the Heinrich-Heine University, founded 1965. The conference attracted more than 340 participants from 24 different countries, including ethicists, basic researchers, virologists, immunologists, molecular biologists and clinicians, as well as numerous students. The event was organised under the auspices of the European Gene Therapy Society by U Hengge of the Department of Dermatology at Heinrich-Heine University. As Dr J Glorioso, President of the American Society for Gene Therapy, pointed out in his welcome address, the skin is a new target for gene therapy, with the potential for in vivo gene transfer to the central nervous system or to the lymphoid organs, for example. As such, Düsseldorf was a perfect location for such a meeting, because the most important biomedical research investments in Germany have been in neurology and dermatology. Many scientific challenges facing this young field of medicine were presented, but there was also much discussion of ethical, regulatory and safety issues with respect to gene therapy.

Clinical Laboratory Techniques↗

UPM3: review of a new molecular diagnostic urine test for prostate cancer.

PSA elevation is the most common indication for urologic referral to rule out the presence of prostate cancer. Recently PSA screening and its usefulness in suggesting the presence of clinically significant prostate cancer has been put into doubt. PSA has limitations in detecting significant cancers even when elevated and on the other hand significant cancers are found in the presence of low PSA levels. In order to better predict patients at risk of harboring prostate cancer new diagnostic tests are required. A promising novel approach is based on the molecular detection of prostate cancer cells in urine. The uPM3 assay is based on the amplification of specific target RNA using the nucleic acid sequence-based amplification (NASBA) technology. In a large multi-center study of 517 cases the overall sensitivity was 66% with a specificity of 89%. The positive (PPV) predictive values for the uPM3 test were 75% compared to 38% for a serum PSA cutoff of 4. The negative predictive value (NPV) was equivalent between the tests, but due to the higher PPV for uPM3, the accuracy of uPM3 was nearly two-fold greater than PSA (81% versus 43% and 47% for PSA cutoffs of 2.5 and 4 ng/ml, respectively). This test may become one of the first molecular diagnostic tools to aid in prostate cancer detection.

Adult↗

Molecular diagnostic techniques for viral hepatitis.

The five different viruses that cause human viral hepatitis, A, B, C, D, and E share the unique property of hepatotropism. Identification of the nucleic acid sequences of each of these viruses, coupled with the application of recombinant DNA technology, has resulted in the rapid development of molecular diagnostic techniques. Currently, molecular hybridization and polymerase chain reaction are the major diagnostic techniques for viral hepatitis. This review discusses the molecular biology of the five hepatitis viruses, the principles of molecular biological techniques, and their current and future diagnostic applications.

Algorithms↗

Fungal molecular diagnostics: a mini review.

Conventional methods to identify fungi have often relied on identification of disease symptoms, isolation and culturing of environmental organisms, and laboratory identification by morphology and biochemical tests. Although these methods are still fundamental there is an increasing move towards molecular diagnostics of fungi in all fields. In this review, some of the molecular approaches to fungal diagnostics based on polymerase chain reaction (PCR) and DNA/RNA probe technology are discussed. This includes several technological advances in PCR-based methods for the detection, identification and quantification of fungi including real-time PCR which has been successfully used to provide rapid, quantitative data on fungal species from environmental samples. PCR and probe based methods have provided new tools for the enumeration of fungal species, but it is still necessary to combine the new technology with more conventional methods to gain a fuller understanding of interactions occurring in the environment. Since its introduction in the mid 1980's PCR has provided many molecular diagnostic tools, some of which are discussed within this review, and with the advances in micro-array technology and real-time PCR methods the future is bright for the development of accurate, quantitative diagnostic tools that can provide information not only on individual fungal species but also on whole communities.

DNA Probes↗

Value of comparative genomic hybridization and fluorescence in situ hybridization for molecular diagnostics in multiple myeloma.

Chromosomal abnormalities, such as 13q deletions, are emerging as important prognostic factors in multiple myeloma. Fluorescence in situ hybridization (FISH) using specific DNA probes is the technique most widely used for the determination of genomic aberrations in this disease. The utility of comparative genomic hybridization (CGH) for molecular diagnostics in plasma cell malignancies has not been systematically analysed. We investigated tumour samples of patients with multiple myeloma (n = 43) or plasma cell leukaemia (n = 3) using CGH and FISH with five DNA probes localized to chromosome bands 1p22, 6q21, 11q22-q23, 13q14 and 17p13. By CGH, the most frequent genomic changes were gains on chromosomes 1q, 9q and 11q, as well as losses on chromosomes 13q, 6q, Xp and Xq. By FISH, trisomy 11q was identified at a similar frequency to the 13q deletion (42%). Compared with FISH data, the sensitivity of CGH was 80.7% and the specificity was 97.5%. Thirty-two aberrations found by FISH were not identified by CGH, mostly as a result of the proportion of cells carrying the respective aberrations, or because of the limited spatial resolution of CGH. Our data indicate that, for clinical molecular diagnostics in multiple myeloma, FISH with a disease-specific DNA probe set is superior to CGH analysis.

Adult↗

[Effect of molecular diagnostic procedures on surgical therapy of malignant diseases].

In the past molecular biological techniques have provided the basis for principally new aspects in the diagnosis of neoplastic diseases. The genetic predisposition to hereditary cancer syndromes can be detected by germ line DNA sequence analysis and offers the opportunity for prophylactic surgery. Some preneoplastic lesions can be detected through the identification of specific molecular alterations in nucleic acid preparations derived from various clinical samples. Residual or disseminated tumor cells can be detected in resection margins, lymph nodes, bone marrow, or peripheral blood with great sensitivity. Most likely, these techniques will strongly influence cancer screening programs and provide a rational basis for adjuvant systemic or regional therapy modalities. However, the clinical value of these techniques has not yet been proven in controlled trials. The problems of reproducibility and quality assurance have to be addressed and solved. This review summarizes the basic principles of some of these new molecular diagnostic techniques to permit a critical assessment of their clinical implications.

Cell Transformation, Neoplastic↗

Experiences with external quality assessment (EQA) in molecular diagnostics in clinical laboratories in Germany. Working Group of the German Societies for Clinical Chemistry (DGKC) and Laboratory Medicine (DGLM).

The German Societies for Clinical Chemistry (DGKC) and Laboratory Medicine (DGLM) have established an official working group on molecular diagnostics in the field of laboratory medicine. The group's objectives are to support the establishment of molecular biology methods for the use in diagnostics in German clinical laboratories. Towards this end, we have defined specific aims, which are 1) the implementation and extension of external quality assessment (EQA) schemes and methodological exercises offered to clinical diagnostic laboratories, 2) the establishment of a proficiency network and data base within the societies, 3) the implementation of an educational program in molecular diagnostic procedures for clinical chemists and laboratory physicians through the organisation of symposia and workshops and 4) the cooperation with other DGKC/DGLM working groups on shared aspects of laboratory analysis, e.g. preanalytics. The focus of this presentation is to introduce some of these goals in more detail with particular emphasis on the first two program aspects and to discuss experiences with these activities.

Clinical Laboratory Techniques↗

A multiplex reverse transcriptase-polymerase chain reaction strategy for the diagnostic molecular screening of chimeric genes: a clinical evaluation on 170 patients with acute lymphoblastic leukemia.

BACKGROUND AND OBJECTIVES: In the last few years molecular methods have allowed the identification of leukemia-associated genetic lesions, which may represent the most accurate predictors of clinical outcome. These considerations strengthen the need for rapid identification of the abnormalities. Our aim was to demonstrate whether a modified multiplex reverse transcription polymerase chain reaction (RT-PCR) system might be successfully used to screen a large number of patients with acute lymphoblastic leukemia (ALL). DESIGN AND METHODS: In this study we adapted the multiplex RT-PCR assay, previously described by Pallisgaard et al., to detect all the most frequent genetic lesions with their characteristic splicing variants occurring in acute lymphoblastic leukemia, such as the MLL/AF4, MLL/ENL, BCR/ABL p190 (e1a2) and p210 (b2a2,b3a2) isoforms, E2A/PBX1, TEL/AML1, SIL/TAL1 and the novel NUP98/RAP1GDS1 transcript, recently described in a T-ALL leukemic subtype. RESULTS: We used the multiplex RT-PCR assay to screen 170 ALL patients (70 children and 100 adults). PCR positivity was detected in 67 (39%) of the 170 ALL patients studied. The comparison between cytogenetic and molecular analyses showed complete correspondence between the two assays in all patients with an evaluable karyotype. Finally, the observed incidence of genetic lesions in our ALL patients was similar to the frequency usually reported both in children and in adults with ALL. INTERPRETATION AND CONCLUSIONS: These results show that, compared to single RT-PCR reactions, our multiplex RT-PCR system allows rapid, specific, simultaneous as well as a less expensive, laborious and time-consuming detection of the most frequent fusion transcripts in ALL patients. Therefore, it might be recommended for rapid diagnostic molecular screening of large numbers of patients, such as those enrolled in multicenter, co-operative studies. Furthermore, we have shown that multiplex RT-PCR is an open system that can easily be adapted to detect new leukemic genes.

Adult↗

Molecular diagnostic tools in Creutzfeldt-Jakob disease and other prion disorders.

Clinical criteria and cerebrospinal fluid biomarkers for the diagnosis of human prion diseases (sporadic, iatrogenic or variant Creutzfeldt-Jakob disease and genetic inherited transmissible spongiform encephalopathies) are now widely available and show a sensitivity and specificity of approximately 98%. Final diagnosis of prion diseases is obtained by post-mortem examination upon identification of the pathological conformer of the prion protein (PrPSc) in the brain. Several diagnostic kits are now available that facilitate the immunochemical measurement of PrPSc. Several new molecular diagnostic techniques, aimed at increasing the sensitivity and specificity of PrPSc detection and at identifying markers of disease other than PrPSc, are the subject of ongoing studies. The aim of these studies is to develop preclinical screening tests for the identification of infected but still healthy individuals. These tests are also essential to investigate the safety of blood or blood-derived products and to ensure meat safety in European countries.

Animals↗

Molecular diagnostics of Charcot-Marie-Tooth disease and related peripheral neuropathies.

DNA diagnostics plays an important role in the characterization and management of patients manifesting inherited peripheral neuropathies. We describe the clinical integration of molecular diagnostics with medical history, physical examination, and electrophysiological studies. Molecular testing can help establish a secure diagnosis, enable genetic counseling regarding recurrence risk, potentially provide prognostic information, and in the near future may be important for the choice of therapies.

Age of Onset↗