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PubMed2005

Laboratory diagnosis of dengue virus infection: current and future perspectives in clinical diagnosis and public health.

Since no protective vaccine or specific treatments are available for dengue fever/dengue hemorrhagic fever (DHF), accurate diagnosis is critical for the early initiation of specific preventive health measures to curtail epidemic spread and reduce economic losses. Commonly used diagnosis methods for confirming dengue infection involve virus isolation, detection of virus antigen or RNA in plasma or serum or tissues, and the presence of dengue virus-specific antibodies in serum and other body fluids. Recently, several techniques have been developed for rapid laboratory diagnosis of dengue virus, including centrifugation amplification to enhance virus isolation rate, the flow cytometry method for early detection of cultured virus, detecting viral nucleic acid e.g., by nested reverse transcriptase-polymerase chain reaction (RT-PCR), quantitative RT-PCR, nucleic acid sequence-based amplification, and real-time PCR, detecting free viral non-structure antigens, anti-dengue virus immunoglobulin M (IgM) or IgG antibodies by enzyme-linked immunosorbent assay, and differentiation of primary versus secondary dengue virus infection. Newly established methods must be standardized to maintain high quality laboratory performance. Laboratory diagnostics must be tailored to a specific laboratory environment, the objectives of clinical needs and the availability of clinical specimens. Speed and accuracy of diagnosis must be balanced against test cost and availability. Future challenges in the study of dengue and DHF include the application of modern techniques, such as nucleic acid chips, protein chips and new biomarkers to avoid cross-reactivity among different serotypes of dengue viruses and other flaviviruses, plus development of internationally standardized guidelines to improve quality assurance of these advanced laboratory tests.

Antibodies, Viral↗
PubMedDate not supplied

[Molecular epidemiologic analysis of the levels of metalloproteases and cyclooxygenase-2 in colorectal cancer].

The aim of this work is the investigation of the level of expression of the vascular endothelial growth factor (VEGF) and metalloproteases (such as Cox-2) in the colon rectal cancer. The final goal is the correlation with liver metastases. Molecular biology approaches will be adopted: in particular: RT-PCR, quantitative real time PCR with fluorescent probes, immunolocalizations and Western blotting This is a proposal of research. The work is under development and results and conclusions cannot be at the moment anticipated. However, in recent publication we found human polyomavirus DNA sequences in colorectal tumors.

Colorectal Neoplasms↗
PubMed2006

[Study on molecular epidemiology of Borna disease virus in Ningxia and vicinal regions].

OBJECTIVE: In order to investigate the epidemics of borna disease virus (BDV) in Ningxia and its vicinal regions. METHODS: p24 fragment of BDV from: (1) peripheral blood mononuclear cells (PBMC) and cerebrospinal fluid mononuclear cells (CSFMC) from 52 patients with viral encephalitis (VE) and 32 healthy donors, (2) peripheral blood mononuclear cells (PBMC) from 53 patients with depressive disorder (DD) and from 360 sheep, were examined by nested reverse transcriptase polymerase chain reaction(PCR) with fluorescence quantitative PCR. Gene sequence and amino acid sequence were analysed for positive product and the molecular epidemiologic characteristics by drawing phylogenetic trees. RESULTS: The positive rate of BDV p24 in CSFMC from VE (11.54%) and in PBMC from DD 11.32% was significantly higher than that in healthy donors (0%) (P < 0.05). The phylogenetic trees indicating the genetic relationship of the p24 fragment of BDV in both sheep and VE, DD in China and was similar to the nucleotide sequence of H1766 strain in Germany. CONCLUSION: Data indicated that the BDV infection was possibly existing in VE, DD patients and health sheep in Ningxia and its vicinal regions with confined locality which called for further study.

Animals↗
PubMed1994

[Polymerase chain reaction in diagnostic pathology].

DNA is a very stable molecule and fixation as well as routine histological processing does not destroy its molecular structure. Hence the possibility exists to use this material for molecular genetic analyses. The polymerase chain reaction (PCR) opens the chance to amplify DNA to huge amounts from pathological paraffin and plastic blocks and to use this DNA for further examinations, such as detection of mutations or translocations in malignant tumors, e.g. t(14;18) in follicular lymphomas, bcr/abl in chronic myeloic leukemia, t(11;22) in Ewing sarcomas or of the ras-gene in colon cancer, overexpression of tumor related mRNA, e.g. mdr1-mRNA of the multidrug associated P-Glycoprotein, or detection of foreign DNA from viruses or bacteriae, as well as analysis of hereditary diseases. PCR in its various forms (conventional PCR, PCR with direct sequencing, reverse transcriptase (RT)-PCR, nested primer PCR, quantitative RT-PCR, inverse PCR, degenerated primer (DOP) PCR, in situ PCR, in situ RT-PCR etc.) has proven to supplement routine diagnostic work in many occasions, however, it has to be emphasized that up to now there exists no example for a complete replacement of histological or immunhistological examination by PCR. As consequence, histology remains the first and most important step towards a relevant diagnosis supplemented e.g. by PCR and other techniques of molecular biology.

Communicable Diseases↗
PubMed1995

Double-differential PCR for gene dosage estimation of erbB oncogenes in benign and cancer tissues and comparison to cellular DNA content.

Competitive and differential quantitative PCR methods circumvent the limiting factors of PCR which cause poor reproducibility. We describe the development and performance evaluation of another quantitative PCR method, double-differential PCR (ddPCR). The ddPCR method comprises the co-amplification of the single-copy gene HBB, the erbB-1, erbB-2 and erbB-3 oncogenes and the second single-copy reference gene SOD2 under equal reaction conditions. The ratio of band intensities of the PCR products in silver-stained polyacrylamide gels expresses the average gene copy number (AGCN) per cell of the erbB oncogenes. The coefficient of variability (CV) was less than 25% for an AGCN of 1. The PCR data were in correlation to the results from dot blotting. DNA image analysis did not reveal any correlation between DNA content and gene dosage deviation of the erbB oncogenes. The method was applied to normal breast tissue, benign breast diseases, breast cancer tissue and lymph node metastases. We suggest this method as being reproducible, low cost and rapid, and therefore suitable for clinical studies on erbB oncogene dosage estimation.

Base Sequence↗
PubMed2000

Real-time PCR for quantitative detection of Toxoplasma gondii.

The protozoan Toxoplasma gondii is one of the most common infectious pathogenic parasites and can cause severe medical complications in infants and immunocompromised individuals. We report here the development of a real-time PCR-based assay for the detection of T. gondii. Oligonucleotide primers and a fluorescence-labeled TaqMan probe were designed to amplify the T. gondii B1 gene. After 40 PCR cycles, the cycle threshold values (C(T)) indicative of the quantity of the target gene were determined. Typically, a C(T) of 25.09 was obtained with DNA from 500 tachyzoites of the T. gondii RH strain. The intra-assay coefficients of variation (CV) were 0.4, 0.16, 0.24, and 0.79% for the four sets of quadruplicate assays, with a mean interassay CV of 0.4%. These values indicate the reproducibility of this assay. Upon optimization of assay conditions, we were able to obtain a standard curve with a linear range (correlation coefficient = 0.9988) across at least 6 logs of DNA concentration. Hence, we were able to quantitatively detect as little as 0.05 T. gondii tachyzoite in an assay. When tested with 30 paraffin-embedded fetal tissue sections, 10 sections (33%) showed a C(T) of <40 and were scored as positive for this test. These results were consistent with those obtained through our nested-PCR control experiments. We have developed a rapid, sensitive, and quantitative real-time PCR for detection of T. gondii. The advantages of this technique for the diagnosis of toxoplasmosis in a clinical laboratory are discussed.

Animals↗
PubMed2004

[Prognostic efficacy for measurement of real-time quantitative PCR-based major bcr/abl mRNA in patients with Philadelphia chromosome-positive leukemia].

Evaluation of minimal residual disease (MRD) provides prognostic information on various hematological malignancies. We describe here the prognostic efficacy of real-time quantitative polymerase chain reaction (RQ-PCR)-based analysis of major bcr/abl mRNA in cases of Philadelphia chromosome-positive leukemia (Ph-leukemia). Twenty-one patients with Ph-leukemia were enrolled as subjects to determine the usefulness of RQ-PCR-based measurement of bcr-abl/abl ratios. Imatinib mesylate (imatinib) was administered to seven of the 21 patients before allogeneic stem cell transplantation (SCT). Hematological relapse or failure of treatment with SCT was observed in 2 of those patients who showed bcr-abl/abl ratios of more than 0.002%, and 5 of the 7 patients showed both RQ-PCR and RT-PCR negativity immediately after SCT. All of the 5 patients who did not receive imatinib before allogeneic SCT showed RQ-PCR negativity immediately after SCT, but the results of RT-PCR were positive in 3 patients at the same time points, and those became negative after donor lymphocyte infusion or the appearance of graft-versus-host disease. Administration of imatinib before SCT was thought to induce an early remission. On the other hand, 8 patients who received imatinib without SCT showed a remarkable decrease in bcr-abl/abl ratios. The ratio gradually rose in one patient with Ph+ALL, enabling prediction of the hematological relapse preceding detection by fluorescence in situ hybridization (FISH) analysis. Standardization of RQ-PCR analysis of bcr-abl mRNA will help to predict early hematological relapse in patients with MRD. In conclusion, it is thought that measurement of RQ-PCR-based major bcr/abl mRNA in patients who were given imatinib and were treated with SCT is useful for the evaluation of MRD and in deciding additional treatment.

Adult↗
PubMed2004

Evaluation of antibiotic susceptibilities of Ehrlichia canis, Ehrlichia chaffeensis, and Anaplasma phagocytophilum by real-time PCR.

We determined MICs of antibiotics against Anaplasma phagocytophilum, Ehrlichia chaffeensis, and Ehrlichia canis by real-time quantitative PCR. The doubling times of the organisms were established: 19 h for E. chaffeensis, 26 h for A. phagocytophilum, and 28 h for E. canis. In comparison to the reference method for determining sensitivities, which uses Diff-Quick staining, our PCR assay was very sensitive and specific. We confirmed that doxycycline and rifampin are highly active against these bacteria and found variable susceptibilities to fluoroquinolones; A. phagocytophilum was susceptible, but E. canis and E. chaffeensis were only partly susceptible. Beta-lactam compounds, cotrimoxazole, macrolide compounds, and telithromycin showed no activity against any of the three organisms. Thiamphenicol was found to be more active than chloramphenicol. For the first time, we showed that these three species have numerous point mutations in their 23S RNA genes, with those at positions 754, 2057, 2058, 2059, and 2611 (Escherichia coli numbering) known to confer resistance to macrolide compounds in other bacteria. The role of each of these mutations in resistance to these drugs should be investigated in the future. Our study confirms previous reports that quantitative PCR is a reliable method for determining antibiotic susceptibility; therefore, it might be useful for screening new drugs.

Anaplasma phagocytophilum↗
PubMed2003

Rapid prenatal diagnosis of aneuploidies and zygosity in multiple pregnancies by amniocentesis with single insertion of the needle and quantitative fluorescent PCR.

OBJECTIVE: To investigate amniotic fluid (AF) samples retrieved in multiple pregnancies by single insertion of the needle, for rapid assessment of chromosome copy number, zygosity, and cross-contamination between fetuses, using Quantitative Fluorescent Polymerase Chain Reaction (QF-PCR) amplification of highly polymorphic microsatellite markers. METHODS: Fifty-two multiple pregnancies were selected (47 twins, 5 triplets) and 108 samples of amniotic fluid were sampled between 12 to 20 weeks of gestation (mean 15.5) using the single-needle technique. Aneuploidy screening by QF-PCR amplification of short tandem repeats (STRs) on chromosomes X, Y, 21, 13, and 18 was carried out within 24 h of collection. Owing to the sampling procedure, the eventual presence of contamination between fetuses was also evaluated in every case. RESULTS: Normal and aneuploid fetuses were readily identified by QF-PCR. Fetal reduction was made available, for trisomic fetuses, without further waiting for completion of fetal karyotyping. In twin gestations, the ultrasound examination of chorionicity was always in agreement with the molecular assessment of zygosity. Contamination between fetuses due to the sampling procedure with a single puncture was never observed. CONCLUSION: Rapid prenatal diagnosis of aneuploidies by QF-PCR is a sensitive, efficient, and reliable assay. When applied in multiple pregnancies, it has the added value of allowing the assessment of zygosity in all cases, independently of chorionicity and fetal sex.

Amniocentesis↗
PubMed2000

Development of a highly sensitive quantitative competitive PCR assay for the detection of murine cytomegalovirus DNA.

Viral persistence and molecular latency are characteristic of infection by the human cytomegalovirus (HCMV). Using the murine cytomegalovirus (MCMV) as a model for human infection, a quantitative-competitive polymerase chain reaction (QC-PCR) assay was developed to detect and quantify MCMV-DNA in the salivary glands of infected mice. The QC-PCR detected high numbers of MCMV DNA copies in the absence of infectious virus. By comparing the DNA content and the results obtained from a standard semiquantitative plaque assay, it is concluded that 1 plaque-forming unit (pfu) is the equivalent of approximately 1500 viral genomes. By day 42-post infection (pi) 4x10(3) copies of DNA/1 mg tissue were sufficient to reactivate infectious virions after cyclophosphamide immunosupression. By day 90 pi, however, when the DNA load was decreased to <1.2x10(2), reactivation was not observed. These results indicate that viral reactivation will occur when the number of infectious DNA copies is equivalent about 2-3 pfu. This quantitative test may therefore help to detect CMV and the risk of reactivation in immunosupressed patients.

Animals↗
PubMed2004

Genes of Helicobacter pylori regulated by attachment to AGS cells.

Reciprocal interactions between Helicobacter pylori and cells of the gastric epithelium to which it adheres may affect colonization. Changes in gene expression of H. pylori induced by adhesion to AGS gastric cancer cells by coculture were compared to changes in gene expression of H. pylori cultured without AGS cells by using cDNA filter macroarrays. Adhesion was quantitatively verified by confocal microscopy of green fluorescent protein-expressing bacteria. Four experiments showed that 22 and 21 H. pylori genes were consistently up- and down-regulated, respectively. The up-regulated genes included pathogenicity island, motility, outer membrane protein, and translational genes. The sigma(28) factor antagonist flgM, flgG, the stress response gene, flaA, omp11, and the superoxide dismutase gene (sodB) were down-regulated. The up-regulation of cag3, flgB, tonB, rho, and deaD was confirmed by quantitative PCR, and the up-regulation of lpxD, omp6, secG, fabH, HP1285, HP0222, and HP0836 was confirmed by reverse transcription (RT)-PCR. The down-regulation of flaA, sodB, and HP0874 was confirmed by quantitative PCR, and the down-regulation of omp11 was confirmed by RT-PCR. The alteration of gene expression in H. pylori after adhesion to gastric cells in vitro suggests that changes in motility, outer membrane composition, and stress responses, among other changes, may be involved in gastric colonization.

Bacterial Adhesion↗
PubMed2004

A differential gene expression profile reveals overexpression of RUNX1/AML1 in invasive endometrioid carcinoma.

Endometrial carcinoma is the most common gynecological malignant disease in industrialized countries. Two clinicopathological types of endometrial carcinoma have been described, based on estrogen relation and grade: endometrioid carcinoma (EEC) and non-EEC (NEEC). Some of the molecular events that occur during the development of endometrial carcinoma have been characterized, showing a dualistic genetic model for EEC and NEEC. However, the molecular bases for endometrial tumorigenesis are not clearly elucidated. In the present work, we attempted to identify new genes that could trigger cell transformation in EEC. We analyzed the differential gene expression profile between tumoral and nontumoral endometrial specimens with cDNA array hybridization. Among the 53 genes for which expression was found to be altered in EEC, the acute myeloid leukemia proto-oncogene, RUNX1/AML1, was one of the most highly up-regulated. The gene expression levels of RUNX1/AML1 were quantified by real-time quantitative PCR, and protein levels were characterized by tissue array immunohistochemistry. Real-time quantitative PCR validated RUNX1/AML1 up-regulation in EEC and demonstrated a specific and significantly stronger up-regulation in those tumor stages associated with myometrial invasion. Furthermore, tissue array immunohistochemistry showed that RUNX1/AML1 up-regulation correlates to the process of tumorigenesis, from normal atrophic endometrium to simple and complex hyperplasia and then, on to carcinoma. These results demonstrate for the first time the up-regulation of RUNX1/AML1 in EEC correlating with the initial steps of myometrial infiltration.

Aged↗
PubMed1995

Rapid detection of selected aneuploidies by quantitative fluorescent PCR.

Selected aneuploidies can be rapidly diagnosed by the analysis of fluorescent polymerase chain reaction (PCR) products of chromosome-specific and highly polymorphic small tandem repeats (STRs). The quantitative STR patterns obtained from samples of normal individuals are markedly different from those seen when patients with aneuploidies involving chromosome X, or trisomies of chromosomes 21 and 18, are tested. For example, while samples from normal subjects--tested with a chromosome 21-derived STR (D21S11)--show two fluorescent PCR peaks with similar activities in a 1:1 ratio, the analysis of samples from patients with trisomy 21 reveals the presence of either three peaks (ratio 1:1:1), or two peaks with a ratio of 2:1. The use of an internal non-polymorphic marker allows identification of trisomic samples with three copies of the same allele. This rapid approach (24 hours) is particularly valuable when applied to prenatal diagnosis of chromosomal abnormalities since it reduces the time of anxiety of the parents waiting for the results of the conventional cytogenetic tests, which require several weeks.

Aneuploidy↗
PubMed2006

Dynamic transition of a methanogenic population in response to the concentration of volatile fatty acids in a thermophilic anaerobic digester.

In this study, the microbial community succession in a thermophilic methanogenic bioreactor under deteriorative and stable conditions that were induced by acidification and neutralization, respectively, was investigated using PCR-mediated single-strand conformation polymorphism (SSCP) based on the 16S rRNA gene, quantitative PCR, and fluorescence in situ hybridization (FISH). The SSCP analysis indicated that the archaeal community structure was closely correlated with the volatile fatty acid (VFA) concentration, while the bacterial population was impacted by pH. The archaeal community consisted mainly of two species of hydrogenotrophic methanogen (i.e., a Methanoculleus sp. and a Methanothermobacter sp.) and one species of aceticlastic methanogen (i.e., a Methanosarcina sp.). The quantitative PCR of the 16S rRNA gene from each methanogen revealed that the Methanoculleus sp. predominated among the methanogens during operation under stable conditions in the absence of VFAs. Accumulation of VFAs induced a dynamic transition of hydrogenotrophic methanogens, and in particular, a drastic change (i.e., an approximately 10,000-fold increase) in the amount of the 16S rRNA gene from the Methanothermobacter sp. The predominance of the one species of hydrogenotrophic methanogen was replaced by that of the other in response to the VFA concentration, suggesting that the dissolved hydrogen concentration played a decisive role in the predominance. The hydrogenotrophic methanogens existed close to bacteria in aggregates, and a transition of the associated bacteria was also observed by FISH analyses. The degradation of acetate accumulated during operation under deteriorative conditions was concomitant with the selective proliferation of the Methanosarcina sp., indicating effective acetate degradation by the aceticlastic methanogen. The simple methanogenic population in the thermophilic anaerobic digester significantly responded to the environmental conditions, especially to the concentration of VFAs.

Anaerobiosis↗
PubMed2001

[Quantitative analysis of human herpes virus type 8 and expression of its genes in patients with multiple myeloma].

OBJECTIVE: To investigate if infection of human herpesvirus type 8 (HHV8) exists in Chinese patients with multiple myeloma (MM), and to identify the relationship between clinical manifestation and the viral load in bone marrow biopsy samples. METHODS: Real-time quantitative PCR was conducted to define the viral load of HHV8 in bone marrow biopsy samples from 23 patients with MM. Nested PCR was conducted to amplify the KS330(233)Bam fragment of HHV8 from peripheral blood mononuclear cells, bone marrow aspirates and bone marrow biopsy samples. RT-PCR was used to study the expression of suspected oncogenes: vIL-6 and vIRF-1 genes. Bone marrow biopsy samples of 5 patients with blood diseases other than MM and 5 patients with non-blood system diseases were used as controls. PCR product of BCBL-1 cell line was used as positive control. RESULTS: (1) The positive rate of HHV8 in bone marrow biopsy samples from patients with MM was 69.6% (16/23) by real-time fluorescence quantitative PCR, and 82.6% (19/23) by nested-PCR. 16 bone marrow samples positive by fluorescence quantitative were positive too by nested-PCR. However, 3 bone marrow samples positive by nested-PCR were negative by fluorescence quantative. HHV8 was positive in only one of the 25 bone marrow aspirates from patients with MM (4%) and in none of the 20 peripharal blood samples from patients with MM. PCR showed negative result in 7 bone marrow aspirates taken form 13 MM patients with positive result by fluorescence quantative PCR. HHV8 was negative in bone marrow biopsy samples from patients with other diseases. HHV8 was negative in the peripheral blood samples from 16 MM patients, among which 9 out of the 11 cases with bone marrow biopsy samples taken showed HHV8 positive by fluorescence quatative PCR. Bone marrow biopsy samples of all patients with other blood diseases and non-blood system diseases were HHV8 negative. RT-PCR showed that among 12 MM patients the expression rate of vIRF-1 was 83.3% (10/12), and expression rate of vIL-6 was 0. The PCR positive products tallied with the sequence of HHV8 DNA. Clinical analysis showed that all of the patients with negative results had had chemotherapy. CONCLUSION: There is a certain association between multiple myeloma pathogenesis and HHV8. In detection of HHVb, nested-PCR is more sensitive than fluorescence quantitaative PCR. The viral gene vILR-1 plays a certain role in the pathogenesis of MM.

Adult↗
PubMed2005

Application of quantitative fluorescent PCR with short tandem repeat markers to the study of aneuploidies in spontaneous miscarriages.

BACKGROUND: Aneuploidies involve approximately 80% of chromosomal anomalies found in spontaneous miscarriages. Since cytogenetic studies show high rates of failure, we have incorporated the quantitative fluorescent polymerase chain reaction (QF-PCR) technique to the study of numerical chromosome anomalies in miscarriages. METHODS: Multiplex and simple QF-PCR assays have been performed on 160 miscarriage and 34 parental DNA samples analysing specific short tandem repeat (STR) markers for chromosomes 2, 7, 13, 15, 16, 18, 21, 22 and X. Cases successfully karyotyped were used as controls in our study. RESULTS: While maternal contamination could be detected in such cases, a molecular result was obtained for 94% of miscarriages without a cytogenetic one. Thirty-six per cent of them were diagnosed with numerical chromosome anomalies. Parental origin of the extra chromosome and the error stage of meiosis could be also determined. CONCLUSIONS: QF-PCR represents a useful and reliable tool to diagnose aneuploidies in spontaneous miscarriages. It provides information about parental and meiotic origin of anomaly, allowing an appropriate genetic counselling.

Abortion, Spontaneous↗
PubMed1997

Measurement of relative quantities of different HLA-A and -B mRNAs in cells by reverse transcription-polymerase chain reaction and denaturing gradient gel electrophoresis.

In order to determine the relative quantities of different HLA-A and -B mRNAs in cells, we have developed a simple and reliable method by using reverse transcription-polymerase chain reaction (RT-PCR), denaturing gradient gel electrophoresis (DGGE) and phosphor imaging analysis. Cytoplasmic RNA from lymphoblastoid cell lines with well-characterized HLA phenotypes are reversely transcribed with a primer specific for all HLA-A and -B antigens. The first-strand cDNA is used as template for quantitative PCR. The primer pair used for quantitative PCR are specific for all class I HLA and one of the primers is labeled with [gamma-32P]ATP. The amplified sequences include parts of exon 2 and exon 3 which contain most polymorphic residues in class I HLA molecules. The RT-PCR products containing the amplified HLA-A and -B sequences are separated by DGGE. The radioactivities of different DNA bands separated in denaturing gradient polyacrylamide gels are measured by phosphor imaging and used to determine the relative amounts of HLA-A and -B mRNAs. This approach is validated by using samples containing known quantities of different HLA-A and -B mRNA transcripts and confirmed by S1 nuclease protection assay. The combined RT-PCR/DGGE approach therefore provides a simple and reliable method for quantitation of relative amounts of different HLA-A and -B mRNAs in cells. This method should also be useful for studying the expression of other highly conserved and duplicated genes.

Cell Line, Transformed↗
PubMed2003

LRIG1 and epidermal growth factor receptor in renal cell carcinoma: a quantitative RT--PCR and immunohistochemical analysis.

In all, 31 renal cell carcinomas (RCCs) were examined for expression of the potential tumour suppressor LRIG1 (formerly Lig-1) and the epidermal growth factor receptor (EGFR). Eight matched samples of uninvolved kidney cortex were also evaluated. Gene expression was examined by quantitative real-time RT-PCR. In the eight matched sample pairs (uninvolved kidney cortex and tumour), protein expression was examined by immunohistochemistry. Conventional (clear cell) tumours showed an expected upregulation of EGFR. LRIG1 expression was generally downregulated in conventional and papillary RCC but not in chromophobic RCC. The ratio between EGFR and LRIG1 was more than 2.5-fold higher in the eight tumours compared with matched uninvolved kidney cortex and was at least two-fold higher than the mean normal ratio in 21 of 31 samples analysed. The observed downregulation of LRIG1 and increased EGFR/LRIG1 ratios are consistent with LRIG1 being a suppressor of oncogenesis in RCC by counteracting the tumour-promoting properties of EGFR. Further studies are justified to elucidate the explicit role of LRIG1 in the oncogenesis of RCC.

Adult↗