The diagnostic value of combined detection of genetic markers and serum protein markers on breast cancer

Objective: The research is to explore the diagnostic value of several detection methods including separated and combined detection of the related genes and related proteins of breast cancer and combined detection of all genetic markers and serum protein markers on breast cancer. Method: The mRNA level expression of the related genes of breast cancer was detected by FQ-PCR technique and the ratio of BRCA-1, Myc, C-erbB2 and β2 micro-globulin was used to express levels of BRCA-1, Myc and C-erbB2; the related proteins of breast cancer were detected through ELISA. Then the research data was analyzed by SPSS19.0 software with t-test as comparison method, and ROC curve was used to calculate the sensitivity, specificity and accuracy of the diagnostic models. Result: No difference can be found among the six indexes in the control group and benign breast tumor group while compared with the benign breast tumor group and the control group, the breast cancer group was significantly different from them; combined detection of genes and that of proteins were both superior to their separated detection; all-marker combined detection was superior to separated detection, which is consistent with combined detection of genes and proteins. Conclusion: More detection indexes will not necessarily outcome better detection effect. Hence, appropriate detection indexes and number are needed to achieve better diagnosis effect. In order to conduct more specific method, more test samples are needed for further researches.

Increased mRNA expression of epidermal growth factor receptor, human epidermal receptor, and survivin in human gastric cancer after the surgical stress of laparotomy versus carbon dioxide pneumoperitoneum in a murine model

BACKGROUND

Surgical impact may be associated with enhanced tumor growth and chemoresistance. This study aimed to evaluate the effect of surgical impact on the mRNA expression of survivin, epidermal growth factor receptor (EGFR), and human epidermal receptor (HER2) in tumors after pneumoperitoneum versus laparotomy.

METHODS

Nude mice were inoculated intraperitoneally with human gastric cancer cells (MKN45). Then laparotomy, carbon dioxide (CO(2)) pneumoperitoneum, and anesthesia alone were performed randomly, after which EGFR, HER2, and survivin mRNA expression using reverse transcription-polymerase chain reaction (RT-PCR) was evaluated.

RESULTS

The expression of EGFR and HER2 mRNA increased significantly after the experiment. However, it was higher after laparotomy than after CO(2) pneumoperitoneum at almost all examined time points. Survivin mRNA expression increased significantly in the first 48 h, then returned to the control level. It was higher after laparotomy than after CO(2) pneumoperitoneum 48 h after the surgical procedures.

CONCLUSION

The expression of EGFR, HER2, and survivin increased after each surgical procedure. However it was lower after CO(2) pneumoperitoneum than after laparotomy. This might be associated with changes in the chemosensitivity of the remnant cancer cells after surgery, supporting the use of minimally invasive surgery for cancer.

ErbB/HER ligands in human breast cancer, and relationships with their receptors, the bio-pathological features and prognosis

BACKGROUND

The aim of this study is to provide an expression profile of ErbB/HER ligands in breast cancer. We analysed the relationships with their receptors, the bio-pathological features and prognosis.

PATIENTS AND METHODS

Epidermal growth factor (EGF), transforming growth factor-alpha (TGFalpha), amphiregulin (AREG), betacellulin (BTC), heparin-binding EGF-like growth factor (HB-EGF), epiregulin (EREG) and neuregulins1-4 (NRG1-4) were quantified in 363 tumours by real-time reverse transcription-polymerase chain reaction using TaqMan probes.

RESULTS

Ligands were detected in 80%-96% of the cases, except NRG3 (42%) and EREG (45.5%). At least one ligand was expressed in 304 cases (cut-off: upper quartile). Almost all combinations of receptor and ligand co-expressions were observed, but TGFalpha is preferentially expressed in tumours co-expressing EGFR/HER3, NRG3 in those co-expressing EGFR/HER4, AREG and EREG in those co-expressing HER2/HER4. EGF and AREG were associated with estradiol receptors, small tumour size, low histoprognostic grading, high HER4 levels. TGFalpha, HB-EGF and NRG2 were negatively related to these parameters. In Cox univariate analyses, EGF was a prognostic factor.

CONCLUSION

Our study demonstrates that (i) ErbB/HER ligands, including BTC and EREG, are expressed in most breast cancers; and (ii) TGFalpha, HB-EGF and NRG2 high expressions are related to the biological aggressiveness of the tumours.

Quantification of homogentisate-1,2-dioxygenase expression in a fungus degrading ethylbenzene

A quantitative real time reverse transcription polymerase chain reaction (qRT-PCR) assay was utilized to quantify the expression of ElHDO in the fungus Exophiala lecanii-corni during the biodegradation of ethylbenzene and other volatile organic pollutants. The assay was applied to measure the impact of pollutant mixtures on ElHDO expression relative to that of a housekeeping gene (18S rRNA). Three compounds were tested in mixtures with ethylbenzene: methyl propyl ketone, phenylacetate and o-xylene. These chemicals repressed, induced, or had no effect on ethylbenzene degradation, respectively. The results demonstrate that the gene target expression value (T(N)) is a useful parameter for evaluating the effect of pollutant mixtures on gene expression. T(N) was found to reflect macroscopic changes in ethylbenzene utilization rates although these two parameters were not related in a linear fashion for all compounds. The assay was log-linear over 5 orders of magnitude of RNA concentration and reproducible between samples (the largest T(N) standard deviation was 20%). The comparative qRT-PCR assay used in this research represents a viable alternative to absolute quantification methods to monitor in situ fungal gene expression in natural and engineered environmental systems.

Relative quantification of ERBB2 mRNA in invasive duct carcinoma of the breast: correlation with ERBB-2 protein expression and ERBB2 gene copy number

The option to treat patients suffering from ERBB-2 protein-positive invasive duct carcinomas of the breast (IDC) with Herceptin requires a precise determination of the ERBB2 status. The aim of the study was to evaluate the ERBB2 mRNA level, placing emphasis on cases with discordant findings between ERBB-2 protein expression (IHC) and a copy number of the ERBB2 gene (FISH). Thirty-nine IDCs (21 cases IHC and FISH concordant, 15 cases moderately discordant, 3 cases markedly discordant) were investigated. ERBB2 mRNA expression was determined using quantitative real-time RT-PCR (Q-RT-PCR). IDCs with negative ERBB-2 protein and without ERBB2 gene amplification had a low ERBB2 mRNA level. Cases with 3+ overexpression of the protein and with strong gene amplification (> 10 copies/tumor cell) had a significantly increased expression of ERBB2 mRNA. In 13 of 15 IDCs with moderate discrepancies (up to 10 copies of the gene per one tumor cell/negative ERBB-2 protein; without amplification/2+ protein) mRNA was low, comparable to that in cases with negative ERBB-2 protein and without ERBB2 gene amplification. In three cases with markedly discordant findings (the gene amplified/protein negative--one case; protein 3+/no amplification--2 cases), Q-RT-PCR results were within a "normal" limit. Ineffective gene amplification and protein accumulation are suggested explanations. Q-RT-PCR revealed two cases with highly expressed ERBB2 mRNA and discordant FISH and/or IHC findings. Increased effectiveness of transcription (protein 2+/high mRNA/without the gene amplification), and combined dysregulation (protein negative/high mRNA/no amplification) are possible causes of these findings. Q-RT-PCR appears useful in clarifying borderline or discrepant IHC and FISH findings.

Current Diagnostic Methods of HER-2/neu Detection in Breast Cancer With Special Regard to Real-Time PCR

In this study we compare different diagnostic methods to measure HER-2/neu gene amplification in breast cancer with special regard to real-time polymerase chain reaction. Fifty specimens of breast cancer were analyzed, and the use of laser-assisted microdissection prior to PCR was investigated. A total of 38 of 50 cases showed HER-2/neu overexpression in immunohistochemistry. In the 2+ scored group, 2 of 23 cases turned out to be amplified after FISH analysis and 14 of 15 cases in the 3+ group were amplified. Of the 16 amplified cases, 3 initially were measured as nonamplified by real-time PCR but showed amplification after laser capture microdissection. One case showed amplification by PCR but turned out to have only one copy of chromosome 17 by FISH. All 0 or 1+ scored cases were measured as nonamplified both by FISH and PCR. Initial concordance rate between FISH and PCR was 92% and could be increased to 98% using laser-assisted microdissection. FISH and PCR showed high diagnostic accuracy and concordance while immunohistochemistry overestimates amplification within the 2+ scored group. Therefore, either FISH or PCR should be applied in cases scored 2+ by immunohistochemistry. Diagnostic accuracy of PCR can be increased using laser-assisted microdissection.

HER-2/neu gene copy number quantified by real-time PCR: comparison of gene amplification, heterozygosity, and immunohistochemical status in breast cancer tissue

BACKGROUND

Amplification of the oncogene HER-2/neu influences breast cancer pathogenesis, and therapy and prognosis may be affected by the degree of amplification. The extent of amplification or protein overexpression typically is analyzed by fluorescence in situ hybridization or immunohistochemistry (IHC), but quantitative PCR techniques have been described that may provide alternatives to these methods.

METHODS

We developed a rapid-cycle, real-time PCR assay for quantification of HER-2/neu gene status. We compared results obtained with this assay with short tandem repeat findings by capillary electrophoresis (CE) and with protein overexpression assessments by IHC. Accuracy and linearity were tested on cell lines and with simulation experiments. We analyzed the amplification of HER-2/neu in 51 clinical tissue samples from patients with suspected breast cancer.

RESULTS

The intra- and interrun CVs for HER-2/neu quantification by real-time PCR were 12% and 18%, and the CV for different simulated amplification and deletion experiments was <7%. The results for HER-2/neu gene status in cell lines matched the values reported in literature. We detected HER-2/neu amplification by real-time PCR in 11 samples, all from patients with invasive ductal carcinoma. Allelic imbalances were found by CE analyses in three samples and by protein overexpression in six samples; five of these were also detected by real-time PCR. Comparison of the quantification results with known prognostic indices yielded results similar to those reported in several other published studies.

CONCLUSIONS

The assay is suitable for accurate and precise quantification of HER-2/neu copy numbers in tumor tissue samples obtained in routine clinical practice.

Electrochemical detection of gene expression in tumor samples: overexpression of Rak nuclear tyrosine kinase

Absolute quantification of Rak nuclear tyrosine kinase mRNA in breast tissue samples was determined by competitive RT-PCR. The total RNA from the same samples was also chemically amplified through conventional RT-PCR, and the relative amounts of these amplified RT-PCR products were determined by adsorption onto an indium tin oxide (ITO) electrode followed by electrochemical detection. The electrochemical detection was performed using the inorganic metal complex Ru(bpy)(3)(2+) (bpy = 2,2' bipyridine) to catalyze the oxidation of the guanine residues of the immobilized RT-PCR products. Using the competitive RT-PCR values as standards, it was found that an optimized conventional RT-PCR coupled with electrochemical detection provides a simple method for measuring relative gene expression among a series of mRNA samples from breast tumors. The use of electrochemical detection potentially eliminates the need for gel electrophoresis and fluorescent or radioactive labels in detecting the target genes.

Quantitative analysis of cytokeratin 20 gene expression using RT-PCR and capillary electrophoresis with fluorescent DNA detection

OBJECTIVE

We developed a quantitative reverse-transcription polymerase chain reaction (RT-PCR) to determine CK20 expression in colorectal tumor and hematopoietic tissue.

DESIGN AND METHODS

Our method incorporates a calibrated PCR with an internal competitor and an external standard.

RESULTS

The RT-PCR assay is sensitive detecting 10 target molecules of CK20 in solution with one round of 38 amplification cycles. Genomic DNA contamination was eliminated by Dnase I digestion of total RNA. The inclusion of a calibrator in the quantitative RT-PCR analysis allowed for a high throughput of unknown samples within the same assay improving comparative analysis between the samples tested. Analysis of peripheral blood and bone marrow from 20 healthy volunteers revealed a low level of CK20 expression in all samples.

CONCLUSION

To study the clinical significance of CK20 expression as a marker of systemic metastatic disease it is essential to measure CK20 mRNA levels in hematopoietic tissue with sensitive quantitative RT-PCR. A sensitive and reproducible method, which is easily performed, is described.

Quantitative Analysis of Aldolase A mRNA in Liver Discriminates between Hepatocellular Carcinoma and Cirrhosis

Background: Chronic liver diseases can progress to cirrhosis and to hepatocellular carcinoma. Timely and unequivocal recognition of the neoplastic evolution of cirrhosis is critical. To this aim, we used a noncompetitive reverse transcription-PCR procedure to analyze aldolase A mRNA in liver tissue from patients with chronic liver diseases at different stages.

Methods: We studied 12 patients with hepatocellular carcinoma, 19 patients affected by chronic hepatitis C or cirrhosis, and 7 healthy controls. Aldolase A mRNA was reverse-transcribed to cDNA, which was then amplified by PCR. The amplified segments were “read” with a novel dot-blot procedure. A calibrator with the same sequence, synthesized in vitro using a T7 phage promoter, was processed at scalar dilutions in parallel to the target samples to generate a calibration curve and so quantify the target mRNA (detection limit, 0.03 amol; linearity spanning five orders of magnitude).

Results: Aldolase A mRNA was ∼10-fold higher in liver biopsies from patients with hepatocellular carcinoma vs patients with chronic hepatitis C or cirrhosis, and healthy individuals. Furthermore, aldolase A mRNA concentrations were 1.2- to 21.3-fold higher in 12 liver biopsies compared with the paired surrounding cirrhotic tissue.

Conclusions: The quantitative analysis of liver tissue aldolase A mRNA differentiates between nonneoplastic chronic liver diseases and hepatocellular carcinoma, which suggests that it has diagnostic potential.

Real-Time Reverse Transcription-PCR Assay for Future Management of ERBB2-based Clinical Applications

Background: Gene amplification/overexpression of ERBB2 (HER2, neu) is a major event in human breast tumorigenesis. ERBB2-based therapeutic agents and ERBB2-specific gene therapy are under development. These new perspectives call for a sensitive and accurate method to screen breast cancer patients for ERBB2 alterations.

Methods: We have developed and validated a real-time quantitative reverse transcription (RT)-PCR assay, based on fluorescent TaqMan methodology, to quantify ERBB2 gene expression at the mRNA level in breast tumors. This recently developed method of nucleic acid quantification in homogeneous solutions has the potential for a wide dynamic range, interlaboratory agreement, and high-throughput capacity without tedious post-PCR processing. The ERBB2 mRNA signal was normalized to the signal for TATA box-binding protein mRNA.

Results: The dynamic range was &gt;1000-fold. The relationship between Ct and log starting concentration was linear (r2 ≥0.99). The mean (SD) normalized expression of ERBB2 in healthy breast tissue was 0.95 (0.37). Overexpression (&gt;5 SD above mean for healthy breast) of the ERBB2 gene was observed (at 3.2- to 135-fold) in 23 (17%) of 134 breast tumor RNA samples. As expected, ERBB2 overexpression was present in all tumors with ERBB2 gene amplification but was uncommon and at a low ratio (&lt;5) in breast cancers without gene amplification.

Conclusions: This new simple, rapid, semi-automated assay is a major alternative to fluorescence in situ hybridization and immunochemistry for gene alteration analysis in human tumors and may be a powerful tool for large randomized, prospective cooperative group trials and to support future ERBB2-based biological and gene therapy approaches.