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PubMed1996

Amplifications of oncogene erbB-2 and chromosome 20q in breast cancer determined by differentially competitive polymerase chain reaction.

A new method of measuring gene copy number in small samples of DNA was used to measure amplification of the erbB-2 gene and of chromosome 20q in breast cancer. This method, termed 'differentially competitive polymerase chain reaction' (DC-PCR) combines the advantages of two other techniques for measuring amplification by PCR, namely differential PCR and competitive PCR. The DC-PCR methodology was evaluated for sensitivity and specificity by comparing amplification of erbB-2 measured by DC-PCR with that obtained by fluorescence in situ hybridization (FISH) for 42 cases or Southern blotting and/or slot blot analysis for 34 cases. There was over 90 percent concordance with both FISH and Southern blotting and/or slot blot analysis. DC-PCR was used to further characterize the newly described amplicon at chromosome 20q. By analyzing DNA from 10 breast cancer cell lines at 7 different loci, we identified a potential common region of amplification of approximately 5 centimorgans at chromosome 20q13 bordered by loci D20S52 and RMC20C100-S1. One hundred and seventeen cases of primary breast cancer were evaluated for amplification at these two loci. Amplification at one or more loci, defined as > 1.5 fold higher copy number than that of normal DNA, was found in 25 cases (21%). Sixteen cases were amplified at only one of the two probes (12 cases for RMC20C001-S1 and 4 cases for D20S52), suggesting that the target gene lies between the two markers or that there are two independent target genes within a small chromosome region.

Blotting, Southern↗

PubMed2006

Detection of HER-2/neu gene amplification in breast carcinomas using quantitative real-time PCR - a comparison with immunohistochemical and FISH results.

The aim of our study was to evaluate the value of quantitative real-time-PCR (qPCR) in the determination of HER-2/neu amplification status of human breast carcinomas by comparing qPCR, FISH and immunohistochemistry results from the same samples. A total of 210 breast carcinomas were examined. Ready-to-use CB11 antibody was applied to detect HER-2/neu oncoprotein expression. In 76 out of 210 cases FISH was performed, and 162 cases were investigated with qPCR. Seventy-five tumors were 2+ or 3+ positive with immunohistochemistry, while 135 samples were either completely negative or 1+. In 45 cases results from all three methods were available. Out of these, in twenty negative and sixteen positive cases both FISH and qPCR led to similar results. The mean qPCR amplification ratio in the concordant positive cases was 5.424 while in the qPCR+/FISH- group the mean ratio was 2.765. Out of 121 samples with scores of 0 or 1+ immunohistochemical result, analyzed also with qPCR, 26 showed HER-2/neu gene amplification. In these cases the mean amplification ratio was 2.53. Comparison of FISH and qPCR together with immunohistochemistry shows that qPCR is more sensitive to detect HER-2/neu gene amplification in tumors scored as 2+ with immunohistochemistry, but the diagnostic cut-off ratio should be defined above 2.7 to avoid high number of false positive cases. Amongst the immunohistochemistry score 2+ cases, 10 of 18 showed gene amplification by qPCR while 10 of 26 by FISH. In conclusion, a well calibrated HER-2/neu qPCR assay may serve as useful alternative to FISH in breast cancer patients.

Adenocarcinoma, Mucinous↗

PubMed2004

Frequent gene amplification and overexpression of decoy receptor 3 in glioblastoma.

The decoy receptor 3 (DcR3) gene is amplified at high frequency in human lung, colon, and liver cancers. DcR3 has been demonstrated to produce a secreted member of the tumor necrosis factor receptor superfamily that negatively regulates Fas-mediated apoptosis. In this study we examined DcR3 gene amplification, DcR3 mRNA expression, and DcR3 protein expression in 46 human astrocytic brain tumors by quantitative genomic PCR, quantitative reverse transcription-PCR, and immunohistochemistry, respectively. The DcR3 gene amplification was detected in none of 6 (0%) low-grade astrocytomas, 1 of 16 (6%) anaplastic astrocytomas, and 6 of 24 ( 25%) glioblastomas. Six of 7 (86%) cases with gene amplification exhibited both mRNA overexpression and/or protein overexpression, suggesting that DcR3 mRNA and protein were expressed more abundantly in the cases with gene amplification. We thus concluded that high DcR3 mRNA expression and protein expression may be positively related to the gene amplification in astrocytic brain tumors, especially glioblastomas. Further, we speculated that the DcR3 gene amplification with overexpression may be responsible for malignant features in glioblastomas.

Adolescent↗

PubMed1990

Structural organization of Acheta rDNA. Evidence for differential amplification of soma and germ-line-specific rDNA sequences.

Amplification is one of the mechanisms whereby the expression of genes can be specifically reinforced. Ribosomal gene amplification in amphibian and insect oocytes is a particularly well documented case. We studied heterogeneity, amplification and size of Acheta domesticus (insects; Orthoptera) ribosomal DNA and characteristics of male and female somatic or germ line rDNAs by analysis of genomic clones from a conventional and a microclone library. The length of the Acheta rDNA repeat unit (transcription unit and non-transcribed spacer (NTS] varied from 47 x 10(3) to 60 x 10(3) base-pairs, with highest variability within the NTS region. Deletions, fragment length heterogeneity and size variability in small steps of individual NTS segments are responsible for the observed size variation. The number of rDNA repeat units per haploid genome of Acheta was determined as 190(+/- 10%). The rDNA is amplified 14(+/- 10%)-fold in the oocyte, producing about 10,000 gene copies per cell. Our results show that the amplification mechanism does not favor individual fragments within the repeat unit. Thus, it can be concluded that amplification does not change the chromosomal characteristics of the rDNA pool. Two fragments specific for oocyte rDNA suggest that the rearrangements accompanying amplification are preferentially located in one distinct EcoRI fragment. Certain regions of Acheta rDNA contain cell-type-specific fragments: it was thus possible to characterize one purely male fragment and a second one specific for male and female soma but not for germ line rDNA. We show that Acheta rDNA reveals a combination of many features reported from different organisms and novel tissue-specific alterations on an extremely large repeat unit. The tissue-specific alterations indicate sexual and soma/germ line differentiation events that are derived by as yet unknown mechanisms.

Animals↗

PubMed1993

The effect of N-myc amplification and expression on invasiveness of neuroblastoma cells.

Most neuroblastomas with N-myc amplification, a sign of extremely poor prognosis, are extensively invasive to surrounding tissues. Therefore, we investigated the relationship between N-myc amplification and invasiveness of neuroblastoma cells, using an in-vitro assay system. Five human neuroblastoma cell lines were used for this study. IMR-32, GOTO, and DZ, all of which had N-myc amplification, showed a highly invasive capacity. In contrast, SK-N-SH without N-myc amplification showed extremely low invasiveness. ST unexpectedly showed high invasiveness in spite of the lack of N-myc amplification. Treatment of GOTO with 10(-5) mol/L all-trans-retinoic acid (RA) for 72 hours markedly decreased both N-myc expression and invasiveness. Treatment of GOTO with 2 mmol/L dibutyryl cyclic AMP (dbcAMP) for 72 hours caused a slight decrease of N-myc expression and invasiveness. These results indicate that N-myc amplification and expression might be closely related to the invasiveness of human neuroblastoma cells.

Cell Movement↗

PubMed1989

Herpes simplex virus-induced "rolling circle" amplification of SV40 DNA sequences in a transformed hamster cell line correlates with tandem integration of the SV40 genome.

Infection with herpes simplex virus leads to amplification of SV40 DNA in various SV40-transformed cells. In earlier studies with the SV40-transformed hamster cell line Elona two different types of DNA amplification could be identified: (i) Bidirectional overreplication of chromosomally integrated SV40 DNA expanding into the flanking cellular sequences ("onion skin" type) and (ii) highly efficient synthesis of extremely large head-to-tail concatemers containing exclusively SV40 DNA ("rolling circle" type). These investigations have indicated that the chromosomally integrated form of SV40 might be the substrate for both types of overreplication. There still had been uncertainties as to whether and how these events were connected. A hypothetical assumption of a recombinational event leading to the excision of SV40 DNA molecules is supported by the results presented here: In this study cloned Elona cell lines were investigated for their ability to amplify SV40 sequences and for the mechanism of amplification utilized. SV40 integration in a partial tandem manner correlates with a strong rolling circle amplification. In contrast, in one cell line harboring a truncated SV40 genome, amplification appears mainly restricted to intrachromosomal bidirectional overreplication. Possible implications for HSV functions involved in the amplification process will be discussed.

Animals↗

PubMed1984

Localization of a cis-acting element responsible for the developmentally regulated amplification of Drosophila chorion genes.

Late in oogenesis two clusters of Drosophila chorion genes and flanking DNA sequences undergo specific amplification in ovarian follicle cells. Lines were constructed using P-element-mediated transformation in which DNA segments derived from the chorion gene cluster at 66D on chromosome III had been inserted at new chromosomal locations. Only transposons that contained a specific 3.8 kb genomic segment derived from the cluster underwent amplification during oogenesis, which occurred with apparently normal tissue and temporal specificity. Adjacent nonchorion sequences also underwent amplification. However, the ability of a transposon to replicate differentially was subject to position effect. These studies provide evidence for the existence of a specific, cis-acting element controlling chorion gene amplification, which includes an origin for disproportionate DNA replication. Attempts to induce amplification with subfragments of the 3.8 kb segment were unsuccessful, suggesting that much of this fragment may be required for amplification.

Animals↗

PubMed1995

Identification of two distinct chromosome 12-derived amplification units in neuroblastoma cell line NGP.

The neuroblastoma cell line NGP contains two homogeneously staining regions (hsr). One of these hsrs contains MYCN sequences. Reverse painting experiments demonstrated that the second HSR consisted of two chromosome 12-derived amplification units, located at 12q14-15 and 12q24. Southern blot and fluorescence in situ hybridization (FISH) analysis showed amplification of genes located at 12q14-15: SAS, MDM2, and CDK4, GLI, CHOP, CDK2, and A2MR were found not to be amplified. FISH further demonstrated amplification of RSN, a gene located at 12q24. The finding of two distinct chromosome 12 amplification units in a neuroblastoma cell line NGP is reminiscent of recent findings in well-differentiated liposarcoma (WDLPS) and other sarcomas. The second amplification unit on chromosome 12 in NGP is located more distal (12q24) than the one observed in WDLPS (12q21). The mechanism and biologic significance of this amplification process in neuroblastoma and WDLPS remain to be elucidated.

Chromosomes, Human, Pair 12↗

PubMed2004

ERBB2 amplifications in esophageal adenocarcinoma.

BACKGROUND: ERBB2 (v-erb-b2 erythroblastic leukemia viral oncogene homolog 2, Her-2-neu) gene amplification and overexpression has been reported in several types of cancer. The purpose of this study was to (1) determine the frequency of ERBB2 amplification (in comparison to other proto-oncogenes) in tumors from patients with esophageal adenocarcinoma, (2) characterize structural details of an ERBB2 amplicon in the esophageal adenocarcinoma cell line OE19 (contains a 100-fold ERBB2 amplification), and (3) test whether growth of the OE19 cell line is sensitive to the ERBB2 inhibitor trastuzumab (Herceptin; Genetech, Inc, San Francisco, CA). METHODS: First, we determined the frequency, by Southern blotting techniques, of amplification of ERBB2 and 13 other proto-oncogenes in a panel of 25 esophageal adenocarcinoma tumors. Then, in a second panel of 10 tumor specimens, expression levels of the ERBB2 gene and of several other genes that flank ERBB2 on chromosome 17 were determined by microarray analysis. Next we characterized the ERBB2 amplicon in the esophageal adenocarcinoma cell line OE19 using cytogenetic methods and a Rec-A protein assisted restriction endonuclease mapping technique. Finally, an in vitro growth inhibition assay was used to measure the sensitivity of OE19 and OE33 cells to treatment with trastuzumab (humanized antibody to ERBB2). RESULTS: ERBB2 was the most frequently amplified proto-oncogene among 25 esophageal adenocarcinoma tumors tested (greater than 10-fold amplification in 3 of 25 (12%) tumors tested). The OE19 cell line contains a 100-fold amplification of the ERBB2 gene, and highly expresses its messenger ribonucleic acid. Transcripts from genes that flank ERBB2 including GRB7, a protein linked to metastasis in esophageal cancer, also showed high levels of expression. In OE19 cells, the ERBB2 amplicon was localized to a homogeneously staining region of chromosome 14. Southern blots from the Rec-A protein assisted restriction endonuclease cleavage mapping experiments in OE19 showed a strong band of 210 kilobases in size, demonstrating that the main amplicon was a tandem repeat. In the in vitro growth inhibition assay, trastuzumab inhibited the OE19 and OE33 cells growth by 49% and 20%, respectively, at a saturating concentration of 20 microg/mL. CONCLUSIONS: ERBB2 is the most frequently amplified proto-oncogene in esophageal adenocarcinoma among the genes that we tested. In the OE19 esophageal adenocarcinoma cell line, the ERBB2 amplicon is translocated onto chromosome 14, is amplified 100-fold at the deoxyribonucleic acid level, and is highly overexpressed at the messenger ribonucleic acid level. Finally, the growth of this cell line was inhibited by incubation with trastuzumab. These results demonstrate that a substantial number of esophageal adenocarcinomas have amplified copies of the ERBB2 gene, and that they may be responsive to ERBB2 targeted therapies such as trastuzumab.

Adenocarcinoma↗

PubMed2004

Amplification and overexpression of genes in 17p11.2 ~ p12 in osteosarcoma.

We summarize and briefly discuss recent findings with respect to the amplification and overexpression of candidate oncogenes in 17p11.2 ~p12 in high-grade osteosarcomas. Amplification of this region occurs in about 25% of cases. The amplification profiles are often complex and suggest the involvement of more than one oncogene. The 17p11.2 ~ p12 region harbors many low-copy repeats (LCRs). We propose LCR-mediated repeated duplication by mitotic nonallelic homologous recombination as mechanism for the generation of the amplifications in this region. Genes PMP22 and COPS3 and three expressed sequence tags from within 17p11.2 ~ p12 have been found to be frequently overexpressed and consistently overexpressed after amplification, which identifies them as candidate oncogenes in this region. Overexpression of COPS3 has been linked to TP53 protein degradation and, being equivalent to TP53 mutation, the induction of genomic instability, which frequently occurs in high-grade osteosarcoma. These findings may serve as a framework for future work aimed to identify the causative oncogenes in 17p11.2 ~p12, to clarify the mechanism of their amplification, and to determine their importance in osteosarcoma tumorigenesis.

Bone Neoplasms↗

PubMed2006

Negative implication of C-MYC as an amplification target in esophageal cancer.

Chromosomal aberrations (amplifications and deletions) underlie the genesis or development of cancer. Amplification of 8q24 is one of the most frequent events in esophageal cancer. To define whether C-MYC is the target gene for 8q24 amplification, we performed fluorescence in situ hybridization using a MYC (8q24.12 approximately q24.13) probe in esophageal cancer from southern China. Furthermore, we detected the expression status of several genes including C-MYC, TRIB1 (alias C8FW), and FAM84B (alias NSE2) in the regions of 8q24 via reverse transcriptase-polymerase chain reaction or immunohistochemical analysis (or both). Distinct amplification of 8q24 was found in esophageal carcinomas. Only 4 of 46 cases showed obvious protein expression in part of the esophageal cancerous nest. In particular, increased protein expression of C-MYC was shown only in a small part of a cancerous nest in the four cases. Positive C-MYC staining was detected mainly in the cytoplasm of esophageal cancer cells. No expression of TRIB1 was detected in esophageal squamous cell carcinomas. Of 59 cases, 39 (66%) cases showed increased expression of FAM84B in esophageal carcinomas. The results suggest that C-MYC and TRIB1 may not be the amplification target of 8q24 in esophageal cancer. FAM84B might be involved in the genesis or development of esophageal cancer in southern China. Whether FAM84B is the amplification target of esophageal cancer awaits further investigation.

Adult↗

PubMedDate not supplied

RNA amplification, fidelity and reproducibility of expression profiling.

We quantitatively address the effect of T7 RNA amplification on expression profiling data, and answer the following questions: (1) What fraction of genes sampled is amplified non-linearly? (2) What is the effect of RNA amplification on comparative expression measurements? (3) If there is amplification bias, is the bias dependent on the degree of amplification or the amount of starting material and (4) Does amplification increase the overall variability of the results? We show that while there is significant amplification bias, the bias is consistent and generally has little effect on array comparisons between amplified samples.

HeLa Cells↗

PubMed2004

HER2/neu gene amplification and protein overexpression in G3 pT2 transitional cell carcinoma of the bladder: a role for anti-HER2 therapy?

HER2/neu is an oncogene encoding a type 1 tyrosine kinase growth factor receptor. Polysomy 17, gene amplification and HER2/neu protein overexpression are associated with a poor prognosis in transitional cell carcinomas (TCC) of the bladder. Due to the application of different laboratory techniques, the exact incidence of HER/neu abnormalities remains uncertain in TCC. Standardised laboratory techniques are therefore important in the determination of the HER2/neu status if an assessment of the potential value of anti-HER2/neu treatments in the clinical management of patients with TCC is to be made. In this study, 75 TCCs with evidence of detrusor muscle invasion at first clinical presentation were included. Gene amplification, polysomy 17 and HER2 copy number were assessed using fluorescence in situ hybridisation (FISH), with separate probes for chromosome 17 and HER2/neu. Protein overexpression was assessed using immunohistochemistry (IHC), with the CB11 antibody and a scoring system evaluating only membranous staining as positive. The mean patient age was 69.5 years (range 42-93 years) and the median survival was 15 months (range 1-156 months). Polysomy 17 occurred in 97%, increased HER/neu copy number in 92% and HER2/neu gene amplification in 7%. Protein overexpression occurred in 57% of cases. Polysomy 17 and HER2/neu protein overexpression are common in G3 pT2 TCCs of the bladder. However, gene amplification is uncommon. Mechanisms other than gene amplification may be responsible for protein overexpression in this tumour type. Evidence from breast cancer suggests that only tumours with HER2/neu gene amplification respond to the anti-HER2/neu therapy trastuzumab (Herceptin). If this were true for bladder cancer, only 4/75 (5%) of G3 pT2 TCCs would be suitable for treatment. The role of trastuzumab in these tumours remains untested at present.

Adult↗

PubMed2005

Epidermal growth factor receptor amplification does not have prognostic significance in patients with glioblastoma multiforme.

PURPOSE: There have been conflicting reports in the literature regarding the prognostic significance of epidermal growth factor receptor (EGFR) amplification in patients with glioblastoma multiforme (GBM). The purpose of this study is to determine the prognostic significance of EGFR amplification in patients with GBM treated at the Cleveland Clinic Foundation. METHODS AND MATERIALS: A retrospective review of GBM patients treated with surgery at the Cleveland Clinic Foundation was performed. Amplification of EGFR was evaluated with fluorescence in situ hybridization in a total of 107 patients diagnosed between December 1995 and May 2003. In addition to EGFR status, various prognostic factors were evaluated to determine the factors that influenced survival and radiographic response rate. The median follow-up was 9 months. RESULTS: The overall median survival was 9.8 months, with a 1-year survival of 40%. Of the 107 patients in whom EGFR status was evaluated, 36 (33.6%) were found to have EGFR amplification. On multivariate analysis, median survival was found to be significantly improved for patients with age < 60 (12.6 months vs. 8 months, p = 0.0061), patients with Karnofsky Performance Status > or = 70 (12.1 months vs. 4.4 months, p < 0.0001), patients who had undergone subtotal resection or gross total resection (11.1 months vs. 4.1 months, p = 0.002), and patients who received a radiation dose > or = 60 Gy compared with no radiation (12.7 months vs. 3 months, p < 0.0001). There was no association of EGFR amplification with survival. When stratified by age (< 60 vs. > or = 60), EGFR status still did not reach statistical significance in predicting for survival. For the 81 patients who had radiographic follow-up, the 1-year overall local control was 14%. On univariate analysis, only treatment with radiation (< 60 Gy vs. > or = 60 Gy vs. no radiation, p = 0.03) was found to predict for improved local control. Treatment with radiation did not remain statistically significant on multivariate analysis. CONCLUSION: Epidermal growth factor receptor amplification was not found to be a significant prognostic indicator of overall survival or radiographic local control in patients with GBM treated with surgery at the Cleveland Clinic Foundation. Further studies are needed to fully delineate the significance of this molecular marker in patients with GBM.

Adult↗

PubMed2004

Gene amplification involves site-specific short homology-independent illegitimate recombination in Acinetobacter sp. strain ADP1.

A system for studying gene amplification in the bacterium Acinetobacter sp. strain ADP1 was used to isolate 105 spontaneous mutants. The method selects for the elevated expression of neighboring transcriptional units in a parent strain lacking its normal transcriptional activators. Gene amplification can compensate for the activator loss by increasing the copy number of seven weakly expressed genes. Mutant colonies arose from the parent strain at a frequency of 10(-8) within three weeks. All but one of these mutants carried tandem head-to-tail repeats of a chromosomal segment (amplicon). These amplicons varied in size from approximately 12-290 kb and ranged in copy number from 3 to more than 30. Gene amplification involved a two-step process in which duplications formed independently of recA. Illegitimate recombination fused normally distant chromosomal regions to create novel DNA duplication junctions. These junctions were isolated from amplification mutants using an assay that exploits Acinetobacter natural transformability. Sequence analysis of 72 junctions revealed little identity in the recombining regions. Furthermore, multiple independently isolated mutants contained identical junctions. Six different junctions, each found in two to six mutants, revealed that some recombination events are site-specific. Several recurring junctions were studied using PCR. In each case, the identical duplication present in the mutant was estimated to have occurred in as many as one in a million cells in populations of strains never exposed to selective conditions. These duplications appeared to form spontaneously by a novel type of short homology-independent, site-specific process. However, in the absence of recA, mutant colonies were not selected from parent cells containing these duplications. Thus, the second gene amplification step most likely depends on homologous recombination to increase amplicon copy number. These studies support the theory that gene amplification is a driving force in the evolution of functionally related gene clusters.

Acinetobacter↗

PubMed2006

Rapid and sensitive detection of heat-labile I and heat-stable I enterotoxin genes of enterotoxigenic Escherichia coli by Loop-Mediated Isothermal Amplification.

We developed a technique for detecting the heat-labile I (LTI) and heat-stable I (STI) genes of enterotoxigenic Escherichia coli (ETEC) using a novel DNA amplification procedure designated Loop-Mediated Isothermal Amplification (LAMP). The detection limit of accelerated LAMP utilizing loop primers was 4 CFU/test for LTI and was 40 CFU/test for STI, which are 10-fold higher than those of conventional PCR assay (detection limit, 40 CFU/test and 400 CFU/test, respectively). No DNA amplification was observed in LT and ST non-producing E. coli or other bacterial strains; thus, high specificity was verified. The specificity of LAMP assay was also confirmed by digestion of LAMP products using restriction enzymes and DNA sequence analysis. In the accelerated LAMP assay, DNA amplification was detected within 35 min, and thus LAMP is superior to conventional PCR in terms of rapidity. It was confirmed that increased concentrations of primers and Bst DNA polymerase could further facilitate the reaction. Furthermore, with the high amplification efficiency of the LAMP assay, amplification can be visually observed by the turbidity caused by magnesium pyrophosphate, a byproduct of the reaction. Detection of LTI and STI in ETEC by LAMP is thus an extremely rapid procedure with high sensitivity and specificity that requires no specialized equipment. This assay is expected to become a valuable tool for rapid diagnosis in ETEC infection.

Bacterial Toxins↗

PubMed2004

ERBB2 amplification is superior to protein expression status in predicting patient outcome in serous ovarian carcinoma.

OBJECTIVE: The objective of this study was to evaluate the frequency and clinical significance of ERBB2 gene amplification in serous ovarian carcinoma. In addition, concordance of the findings of ERBB2 immunohistochemistry and ERBB2 amplification was assessed. METHODS: Tissue microarray constructed of 401 serous ovarian carcinomas was examined by chromogenic in situ hybridization (CISH) using probe for ERBB2 gene and by immunohistochemistry using CB11 monoclonal antibody against ERBB2 protein. RESULTS: Amplification (>5 copies per cell) of ERBB2 was detected in 7% and low copy number increase (three-five copies) in 14% of the carcinomas. Increased copy number of ERBB2 was associated with poor prognosis, that is, poor response to therapy (P = 0.024), shorter disease-free (P < 0.0001) and overall survival (P < 0.0001). ERBB2 copy number status was identified as an independent prognostic factor for overall survival. Increased copy number of ERBB2 was also associated with high tumor grade, greater patient age, large residual tumor size, high proliferation index, aberrant p53 and negative progesterone receptor status. A significant association was found between ERBB2 amplification and ERBB2 protein overexpression. However, a substantial number of cases showed discrepant results by the two methods, especially in cases with low-level amplification or moderate protein overexpression. Overexpression of ERBB2 protein was associated with poor overall survival, but the prognostic value was weaker than that of ERBB2 gene copy number status. CONCLUSION: ERBB2 amplification positive tumors identified by CISH constitute a subgroup of serous ovarian carcinomas associated with aberrant p53, negative progesterone receptor status and aggressive behavior, a suitable group for testing the effect of trastuzumab in clinical trials.

Cystadenocarcinoma, Serous↗

PubMed2004

Rates of topoisomerase II-alpha and HER-2 gene amplification and expression in epithelial ovarian carcinoma.

OBJECTIVES: Topoisomerase II-alpha (T2a) is being actively investigated as a potential predictive marker of response to anthracyclines in breast cancer (BC). Although the role of T2a inhibitors as upfront and salvage treatment for epithelial ovarian carcinoma (EOC) remains unclear, we speculated that a small subgroup of ovarian cancer patients could derive a selective benefit from these agents. In this study, we investigated the actual rates of T2a and HER-2 amplification and overexpression by fluorescence in situ hybridisation (FISH) and immunohistochemistry (IHC), respectively. METHODS: Seventy-three samples of chemotherapy-naive patients with EOC were selected from our archives. FIGO stage and histology were available for most patients. RESULTS: Based on arbitrary cut-offs of > or =1.5 and > or =2 (ratio copies/centromere17), amplification rates for HER-2 were 15/64 (23.4%) and 8/64 (12.5%) versus 16/64 (25%) and 5/64 (7.8%) for T2a. We found only 3/72 (4.2%) cases of HER-2 overexpression (3+) versus 15/70 (21.4%) for T2a (staining of >10% of the cells). There was a modest correlation between T2a amplification and overexpression (P=0.01) and a strong correlation between T2a and HER-2 amplification when these markers were analysed as continuous variables (P<0.001). T2a amplification significantly correlated with advanced FIGO stage (P=0.02). CONCLUSION: The assessment of HER-2 and T2a amplification and overexpression by FISH and IHC, respectively, is feasible in EOC. These tests can be used for large-scale evaluation of the potential predictive and prognostic value of these markers in the future. Further studies with a special focus on T2a are needed to determine the best cut-offs for potential clinical use in the future.

Antigens, Neoplasm↗