Highly sensitive detection of the MGB1 transcript (mammaglobin) in the peripheral blood of breast cancer patients

Prognostic role of plasma mammaglobin A expression in breast carcinoma patients: a meta-analysis

Mammaglobin A expression in peripheral blood (PB) of breast carcinoma patients has been evaluated by various studies, but the findings have been inconsistent. This meta-analysis aimed to clarify the prognostic value of mammaglobin A in the PB of breast carcinoma patients and define its relationships with clinicopathological features. PubMed, EMBASE, and the Cochrane Library databases were systematically searched for eligible studies through September 26, 2017. A total of 20 studies involving 2,323 patients were analyzed, and the data were independently extracted by two researchers. The combined hazard ratios (HRs) with 95% CI was used to assess the association between survival data and plasma mammaglobin A expression, and odds ratios (ORs) and 95% CIs were used to assess the associations between clinicopathological parameters and plasma mammaglobin A expression. The results indicated that plasma mammaglobin A expression was a predictor of poor prognosis for breast carcinoma patients, with an HR of 2.08 (95% CI=1.48–2.91; P<0.0001) for overall survival. Moreover, plasma mammaglobin A was significantly associated with lymph node metastasis (OR=2.00; 95% CI=1.17–3.45; P=0.01) and advanced tumor stage (OR=3.01; 95% CI=1.57–5.77; P=0.0009) in breast carcinoma patients. However, the results revealed that plasma mammaglobin A was not significantly associated with tumor size (OR=1.29; 95% CI=0.46–3.66; P=0.63), tumor differentiation (OR=0.99; 95% CI=0.63–1.57; P=0.97), menopausal status (OR=0.75; 95% CI=0.48–1.18; P=0.22), estrogen receptor status (OR=0.78; 95% CI=0.44–1.36; P=0.38), progesterone receptor status (OR=0.76; 95% CI=0.57–1.02; P=0.07), or human epidermal growth factor receptor 2 status (OR=1.12; 95% CI=0.78–1.59; P=0.54). In conclusion, the results demonstrate that positive plasma mammaglobin A expression might serve as a biomarker of poor prognosis for breast carcinoma patients.

Detection of mammaglogin A in blood from breast cancer patients, before and after treatment, using a one-tube nested PCR protocol. Association with the absence of tumor estrogen receptors

OBJECTIVE

A one-tube nested RT-PCR protocol was set up and used to detect mammaglobin A (MGA) expression in blood samples from breast cancer patients. The correlation of MGA detection with prognostic factors was analyzed.

DESIGN AND METHODS

Total RNA from nucleated blood cells was extracted from 65 breast cancer patients (before surgery and after the treatments) and 18 healthy subjects and used to detect MGA expression by a modified nested RT-PCR.

RESULTS

MGA expression was detected in 38.4% of patients before surgery, and in 50% and 36.8% of post-treatment samples from patients that expressed MGA or were MGA negative before surgery, respectively. MGA detection was associated with the absence of tumor estrogen receptors (p=0.004).

CONCLUSIONS

MGA detection by the modified nested RT-PCR is a specific marker for circulating tumor cells in patients with breast carcinoma and a negative prognostic factor for the disease.

Human mammaglobin: a superior marker for reverse-transcriptase PCR in detecting circulating tumor cells in breast cancer patients

Breast cancer is the most frequent cancer in women in the USA and the second most common cause of death in females who develop cancer. Recently, the detection of circulating tumor cells has emerged as a promising tool for monitoring the progression of clinically occult micrometastases in breast cancer patients. Sensitive molecular techniques, primarily based upon the reverse-transcriptase PCR, using various molecules as markers, have been developed to detect circulating tumor cells. Among those molecules, human mammaglobin mRNA has been found to be the most specific marker for the hematogenous spread of breast cancer cells. In this article, we review the current knowledge regarding the use of reverse-transcriptase PCR for detecting human mammaglobin mRNA as a biomarker for circulating tumor cells in breast cancer patients, and evaluate the clinical implications of human mammaglobin since it was first isolated in 1996.

Relevance of circulating tumor cells, extracellular nucleic acids, and exosomes in breast cancer

Early detection of cancer is vital to improved overall survival rates. At present, evidence is accumulating for the clinical value of detecting occult tumor cells in peripheral blood, plasma, and serum specimens from cancer patients. Both molecular and cellular approaches, which differ in sensitivity and specificity, have been used for such means. Circulating tumor cells and extracellular nucleic acids have been detected within blood, plasma, and sera of cancer patients. As the presence of malignant tumors are clinically determined and/or confirmed upon biopsy procurement-which in itself may have detrimental effects in terms of stimulating cancer progression/metastases-minimally invasive methods would be highly advantageous to the diagnosis and prognosis of breast cancer and the subsequent tailoring of targeted treatments for individuals, if reliable panels of biomarkers suitable for such an approach exist. Herein, we review the current advances made in the detection of such circulating tumor cells and nucleic acids, with particular emphasis on extracellular nucleic acids, specifically extracellular mRNAs and discuss their clinical relevance.

Coexistence of alternative MLL-SEPT9 fusion transcripts in an acute myeloid leukemia with t(11;17)(q23;q25)

We present the characterization at the RNA level of an acute myeloid leukemia with a t(11;17)(q23;q25) and a MLL rearrangement demonstrated by FISH. Molecular analysis led to the identification of two coexistent in-frame MLL-SEPT9 fusion transcripts (variants 1 and 2), presumably resulting from alternative splicing. Real-time quantitative RT-PCR analysis showed that the relative expression of the MLL-SEPT9 fusion variant 2 was 1.88 fold higher than the relative expression of MLL-SEPT9 fusion variant 1. This is the first description of a MLL-SEPT9 fusion resulting in coexistence of two alternative splicing variants, each of which previously found isolated in myeloid leukemias.

Gene expression of circulating tumour cells in breast cancer patients

Background

The diagnostic tools to predict the prognosis in patients suffering from breast cancer (BC) need further improvements. New technological achievements like the gene profiling of circulating tumour cells (CTC) could help identify new prognostic markers in the clinical setting. Furthermore, gene expression patterns of CTC might provide important informations on the mechanisms of tumour cell metastasation.

Materials and methods

We performed realtime-PCR and multiplex-PCR analyses following immunomagnetic separation of CTC. Peripheral blood (PB) samples of 63 patients with breast cancer of various stages were analyzed and compared to a control group of 14 healthy individuals. After reverse-transcription, we performed multiplex PCR using primers for the genes ga733.3, muc-1 and c-erbB2. Mammaglobin1, spdef and c-erbB2 were analyzed applying realtime-PCR.

Results

ga733.2 overexpression was found in 12.7% of breast cancer cases, muc-1 in 15.9%, mgb1 in 9.1% and spdef in 12.1%. In this study, c-erbB2 did not show any significant correlation to BC, possibly due to a highly ambient expression. Besides single gene analyses, gene profiles were additionally evaluated. Highly significant correlations to BC were found in single gene analyses of ga733.2 and muc-1 and in gene profile analyses of ga733.3*muc-1 and GA7 ga733.3*muc-1*mgb1*spdef.

Conclusion

Our study reveals that the single genes ga733.3, muc-1 and the gene profiles ga733.3*muc-1 and ga733.3*3muc-1*mgb1*spdef can serve as markers for the detection of CTC in BC. The multigene analyses found highly positive levels in BC patients. Our study indicates that not single gene analyses but subtle patterns of multiple genes lead to rising accuracy and low loss of specificity in detection of breast cancer cases.

Sentinel lymph node molecular pathology in breast carcinoma

OBJECTIVES

The prognosis of breast cancer patients depends on primary tumor resection and axillary lymph nodes examination. The purpose of this study was to analyze by molecular biology techniques the presence of mammaglobin A and B messenger RNA in breast sentinel lymph node (SLN) by reverse-transcription polymerase chain reaction (RT-PCR).

METHODS

Sentinel lymph nodes from 50 patients with a diagnosis of breast cancer were prospectively studied between June 2004 and August 2006. Lymph nodes were all examined every 2 mm by intraoperative cytology. Hematoxylin-eosin (HE), immunohistochemistry (IHC) with cytokeratin (clone AE1-AE3, DAKO, dilution 1:100), and molecular biology techniques were used in all cases.

RESULTS

Deferred study with routine techniques showed subcapsular metastasis in 3/50 cases. Out of 50 cases, 5 were detected with IHC, and 2 of them were negative for HE. Multiplex RT-PCR allowed the detection of 18/50 positive SLN, which included the 5 above-mentioned cases. The other SLN studied (32/50) showed no metastases with the methods herein implemented.

CONCLUSIONS

The epidemiologic impact of incomplete SLN study has been observed, as the HE technique fails to identify all SLN with micrometastases. In our opinion, SLN should be studied with IHC and molecular biology techniques. The multiplex RT-PCR technique for A and B mammaglobin proves to be specific and sensitive. This study will serve to formulate hypotheses. Further research, including a larger population and a longer-term follow-up period, will be required to confirm these hypotheses. Should our findings be confirmed in the future, molecular biology determinations could modify patients' staging and treatment.

The detection of circulating tumor cells of breast cancer patients by using multimarker (Survivin, hTERT and hMAM) quantitative real-time PCR

OBJECTIVES

To develop a specific, reliable assay for detecting circulating tumor cells (CTC) in peripheral blood of breast cancer patients.

DESIGN AND METHODS

94 breast cancer patients, 35 patients with benign breast tumor, 40 healthy individuals, and 25 patients with other solid tumors were evaluated by quantitative real-time reverse transcription-PCR (qRT-PCR) for detecting Survivin, hTERT, and hMAM mRNA in peripheral blood (PB) of breast cancer patients. In addition, analyses were carried out for their correlation with patients' clinicopathologic features.

RESULTS

The sensitivity of Survivin, hTERT, and hMAM mRNA in the PB of breast cancer patients was 36.2%, 59.6% and 33.0%, respectively. Survivin and hTERT were detected in the PB patients with solid tumors other than breast cancer, but hMAM mRNA was only detected in breast cancer patients. The sensitivity of three combined markers in the parallel test was 70.2%.Compared to that of single marker detection, the three combined markers' percentage was significantly higher. However, the specificity of three combined markers of serial test was 100%. The expression of the three mRNAs significantly correlated with TNM stage, and lymph node metastasis.

CONCLUSIONS

Survivin, hTERT and hMAM mRNA assays are powerful methods for detection of CTC of breast cancer patients. With combination of the three markers for detection of CTC of breast cancer, the parallel test increases the sensitivity. This analysis can offer a simple, noninvasive, and promising adjuvant tool for the early detection of micrometastatic tumor cells in breast cancer patients.

Detection of mammaglobin mRNA in peripheral blood is associated with high grade breast cancer: interim results of a prospective cohort study

BACKGROUND

We sought to examine the detection rate of cancer cells in peripheral blood (PBL) and in bone marrow (BM) using an established 7-gene marker panel and evaluated whether there were any definable associations of any individual gene with traditional predictors of prognosis.

METHODS

Patients with T1-T3 primary breast cancer were enrolled into a prospective, multi-institutional cohort study. In this interim analysis 215 PBL and 177 BM samples were analyzed by multimarker, real-time RT-PCR analysis designed to detect circulating and disseminated breast cancer cells.

RESULTS

At a threshold of three standard deviations from the mean expression level of normal controls, 63% (136/215) of PBL and 11% (19/177) of BM samples were positive for at least one cancer-associated marker. Marker positivity in PBL demonstrated a statistically significant association with grade II-III (vs. grade I; p = 0.0083). Overexpression of the mammaglobin (mam) gene alone had a statistically significant association with high tumor grade (p = 0.0315), and showed a trend towards ER-negative tumors and a high risk category. There was no association between marker positivity in PBL and the pathologic (H&E) and/or molecular (RT-PCR) status of the axillary lymph nodes (ALN).

CONCLUSION

This study suggests that molecular detection of circulating cancer cells in PBL detected by RT-PCR is associated with high tumor grade and specifically that overexpression of the mam gene in PBL may be a poor prognostic indicator. There was no statistically significant association between overexpression of cancer-associated genes in PBL and ALN status, supporting the concept of two potentially separate metastatic pathways.

DNA-probes for the highly sensitive identification of single nucleotide polymorphism using single-molecule spectroscopy

This article presents a new, highly sensitive method for the identification of single nucleotide polymorphisms (SNPs) in homogeneous solutions using fluorescently labeled hairpin-structured oligonucleotides (smart probes) and fluorescence single-molecule spectroscopy. While the hairpin probe is closed, fluorescence intensity is quenched due to close contact between the chromophore and several guanosine residues. Upon hybridization to the respective target SNP sequence, contact is lost and the fluorescence intensity increases significantly. High specificity is achieved by blocking sequences containing mismatch with unlabeled oligonucleotides. Time-resolved single-molecule fluorescence spectroscopy enables the detection of individual smart probes passing a small detection volume. This method leads to a subnanomolar sensitivity for this single nucleotide specific DNA assay technique.

The clinical significance of disseminated tumor cells in breast cancer

The presence of tumor cells in the bone marrow of primary breast cancer patients at surgery has been shown to be an independent prognostic indicator of relapse. Tumor cells have been detected either directly, using immunocytochemical staining, or indirectly, using reverse transcription-polymerase chain reaction (RT-PCR). Studies have been initiated to determine whether the presence of disseminated cells can be monitored during the therapy of patients with primary breast cancer, and thus potentially be used to predict relapse before overt metastases are detectable. Studies are also ongoing to improve methods of detection, such as immunobead enrichment followed by staining and real-time RT-PCR, and to find alternative markers for the disseminated cells. Studies of patients with overt metastases have shown that there is a large tumor load in the peripheral blood and that this predicts overall survival. This article reviews the published literature on studies carried out in both primary and metastatic breast cancer patients, the methodologies and markers used, and improvements in detection methodologies that are being investigated including real-time RT-PCR, novel markers, enrichment and automated image analysis.

Molecular detection of EGFRvIII-positive cells in the peripheral blood of breast cancer patients

The aim of this study is to evaluate epidermal growth factor receptor variant III, EGFRvIII, a cancer specific mutant, as a possible marker for the diagnosis of breast cancer occult systemic disease. EGFRvIII mRNA was identified by an RT-nested PCR with a high sensitivity. In 102 women studied, the mutant was detected in the peripheral blood of 30% of 33 low risk, early stage patients, in 56% of 18 patients selected for neoadjuvant chemotherapy, in 63.6% of 11 patients with disseminated disease and 0% of 40 control women. In low risk, early stage patients, the presence of one or more tumour characteristics predicting recurrence such as the absence of oestrogen receptors and the presence of ERBB2 or histologic grades G2/G3 was significantly associated with EFGRvIII detection (p<0.05). EGFRvIII mRNA has characteristics to be a useful marker for the diagnosis of occult systemic disease in breast cancer. Follow-up studies will evaluate its clinical value as a decision criterion for systemic therapy.

Detection of Mammaglobin A-mRNA-positive circulating tumor cells in peripheral blood of patients with operable breast cancer with nested RT-PCR

OBJECTIVES

The development and validation of a nested RT-PCR methodology for the detection of Mammaglobin A-mRNA-positive circulating tumor cells in peripheral blood of patients with operable breast cancer and evaluation of its prognostic significance.

DESIGN AND METHODS

Different combinations of specific primers were in silico designed and selected, so that false positive results due to genomic DNA contamination were avoided. The specificity of the primers used was evaluated in 30 healthy individuals, 20 patients with colorectal cancer and 20 patients with non-small cell lung cancer. The method was applied in 101 patients with operable breast cancer before the administration of adjuvant chemotherapy and 39 patients with metastatic breast cancer.

RESULTS

Mammaglobin A-mRNA-positive cells were detected in 14/101 (13.9%) of early breast cancer patients but not in the control population studied (0%); 9 of them (64.3%) relapsed during the follow-up period. Mammaglobin A was detected in 7/39 (17.9%) of patients with verified metastasis. Multivariate analysis revealed the detection of Mammaglobin A-mRNA-positive cells, as an independent risk factor for reduced DFI.

CONCLUSIONS

Mammaglobin A is a highly specific molecular marker for the detection of circulating tumor cells in operable breast cancer, with important prognostic applications.

Tumor cell detection in peripheral blood and bone marrow

PURPOSE OF REVIEW

Whether the occurrence of tumor cells in peripheral blood or bone marrow from patients with solid tumors is predictive for disease recurrence or of any other prognostic relevance remains unknown. This article reviews recently published results focusing on the various methods used, their correlations with clinical or biological parameters and their potential prognostic value.

RECENT FINDINGS

An increasing number of marker genes and different techniques, alone or in combinations, have been used for the detection of tumor cells in peripheral blood and bone marrow. Various results obtained are hardly comparable, most often due to the different methods in use. The frequency of circulating tumor cells in peripheral blood varied within a broad range and their clinical relevance appeared to be contradictory, at least in part. Disseminated tumor cells in bone marrow reached an independent prognostic value in breast cancer patients, but several investigations led to inconsistent correlations with clinical or prognostic criteria.

SUMMARY

Still many questions remain unanswered; hence, the detection of tumor cells in peripheral blood or bone marrow cannot yet be taken into account for therapeutic decisions.

RT-PCR determination of maspin and mammaglobin B in peripheral blood of healthy donors and breast cancer patients

BACKGROUND

The aim of the present study was to evaluate the accuracy of two markers, maspin and mammaglobin B, singly or in combination, to detect breast cancer. To define better the potential and limits of the two markers for diagnostic purposes, blood positivity was analyzed in relation to clinical, pathological and biological tumor characteristics.

PATIENTS AND METHODS

The markers were determined in peripheral blood (PB) samples from 27 healthy donors and 140 previously untreated patients using nested reverse transcriptase polymerase chain reaction (RT-PCR).

RESULTS

Positivity for maspin in blood samples was observed in 24% of patients with an 89% specificity. For mammaglobin B, positivity was observed in 7% of patients and never in healthy donors. The presence of maspin was correlated with cell proliferation of the primary tumor (P = 0.015), whereas mammaglobin B positivity correlated with pathological stage (P = 0.013). The presence of either marker was significantly related to nodal status.

CONCLUSIONS

Our results indicate that the two markers in association could represent a potentially useful non-invasive tool to detect breast cancer. The validation of these markers as indicators of high risk of relapse is ongoing in a series of patients with an adequate follow-up.