CK-19 expression by RT-PCR in the peripheral blood of breast cancer patients correlates with response to chemotherapy

Cytokeratin 19 Expression by Reverse Transcriptase-Polymerase Chain Reaction in the Peripheral Blood of Prostate Cancer Patients

Aims and background

Sensitive reverse transcriptase-polymerase chain reaction-based techniques for detection of epithelial antigen expression, such as cytokeratin 19, in the peripheral blood mononuclear fraction of prostate cancer patients may allow the detection of tumor progression at A molecular level.

Methods

We studied cytokeratin 19 expression by reverse transcriptase-polymerase chain reaction in peripheral blood mononuclear cell samples of 10 control men and serially in 44 patients with prostate cancer every three months for 18 months.

Results

None of the 10 normal control men expressed cytokeratin 19 in their peripheral blood mononuclear fraction. In the patients, cytokeratin 19 positivity at entry was not associated with age, Gleason score, clinical stage, prostate-specific antigen or alkaline phosphatase. Interestingly, having at least one positive cytokeratin 19 result during follow-up correlated significantly with time to prostate-specific antigen progression (P = 0.049), especially in the subgroup of metastatic patients (P = 0.032).

Conclusions

We conclude that cytokeratin 19 expression by reverse transcriptase-polymerase chain reaction in the peripheral blood mononuclear cell fraction of prostate cancer patients correlates with time to prostate-specific antigen progression. Further studies are needed to confirm these findings.

A New Nested Primer Pair Improves the Specificity of Ck-19 Mrna Detection by Rt-Pcr in Occult Breast Cancer Cells

Reverse transcription polymerase chain reaction (RT-PCR) of cytokeratin-19 (CK-19) has been widely used to detect small numbers of circulating malignant epithelial cells in the bone marrow or the peripheral blood of patients with breast cancer. However, a high percentage of false positive results has been recorded and conflicting reports question the clinical relevance of this technical approach. We demonstrate that the use of a new nested primer pair for CK-19 RT-PCR avoids false positive results without affecting the sensitivity of the assay. Our experiments were carried out using MCF-7 cells alone or mixed with peripheral blood mononuclear cells (PBMNC) of healthy donors. The results were also validated in a large series of healthy donors and in a preliminary study on a limited number of patients with breast cancer, thus suggesting that our assay is feasible for application in the clinical evaluation of occult malignant epithelial cells.

Gene profiling and circulating tumor cells as biomarker to prognostic of patients with locoregional breast cancer

The gene profile of primary tumors, as well as the identification of circulating tumor cells (CTCs), can provide important prognostic and predictive information. In this study, our objective was to perform tumor gene profiling (TGP) in combination with CTC characterization in women with nonmetastatic breast cancer. Biological samples (from peripheral blood and tumors) from 167 patients diagnosed with stage I, II, and III mammary carcinoma, who were also referred for adjuvant/neoadjuvant chemotherapy, were assessed for the following parameters: (a) the presence of CTCs identified by the expression of CK-19 and c-erbB-2 in the peripheral blood mononuclear cell (PBMC) fraction by quantitative reverse transcription PCR (RT-PCR) and (b) the TGP, which was determined by analyzing the expression of 21 genes in paraffin-embedded tissue samples by quantitative multiplex RT-PCR with the Plexor® system. We observed a statistically significant correlation between the progression-free interval (PFI) and the clinical stage (p = 0.000701), the TGP score (p = 0.006538), and the presence of hormone receptors in the tumor (p = 0.0432). We observed no correlation between the PFI and the presence or absence of CK-19 or HER2 expression in the PBMC fraction prior to the start of treatment or in the two following readouts. Multivariate analysis revealed that only the TGP score significantly correlated with the PFI (p = 0.029247). The TGP is an important prognostic variable for patients with locoregional breast cancer. The presence of CTCs adds no prognostic value to the information already provided by the TGP.

Circulating tumour cell analysis as an early marker for relapse in stage II and III colorectal cancer patients: a pilot study

INTRODUCTION

Recent studies have identified both the prognostic and predictive utility of determining the number of circulating tumour cells (CTC) in patients with solid cancers.

MATERIAL AND METHODS

In the present pilot study we evaluated the ability of two different methods to isolate CTC in combination with two strategies to enumerate CTC from patients with stages II and III surgically treated colorectal cancer (CRC). First, we used two systems for tumour cell enrichment (differential centrifugation and immunomagnetic beads), combined with two methods to enumerate CTC (real-time PCR and fl ow cytometry), to determine the most efficient combination. These experiments were performed in a model system using serial dilutions of HT29 tumour cell lines with lymphocytes. Then, CTC analysis using the technical approach selected before was performed in 109 blood samples from 16 stage II and III CRC patients during chemotherapy treatment and follow-up.

RESULTS

Immunomagnetic beads followed by flow cytometry was the most efficient combination (ED=60.53; p=0.5). Two cases out of 16 patients analysed had clinical tumour relapse. In both, we detected a significant increase of CTC five and six months, respectively, before the relapse was clinically evidenced. An increase of CTC was also observed in another case without clinical evidence of relapse. The remaining cases (13) had very few or no detectable CTC and no clinical evidence of relapse (p=0.029).

CONCLUSIONS

Changes in CTC numbers during follow-up might predict tumour relapse. Further evaluation of CTC prognostic and predictive value in patients with early CRC is warranted.

Circulating tumor cells (CTCs): detection methods and their clinical relevance in breast cancer

The enumeration of circulating tumor cells has long been regarded as an attractive diagnostic tool, as circulating tumor cells are thought to reflect aggressiveness of the tumor and may assist in therapeutic decisions in patients with solid malignancies. However, implementation of this assay into clinical routine has been cumbersome, as a validated test was not available until recently. Circulating tumor cells are rare events which can be detected specifically only by using a combination of surface and intracellular markers, and only recently a number of technical advances have made their reliable detection possible. Most of these new techniques rely on a combination of an enrichment and a detection step. This review addresses the assays that have been described so far in the literature, including the enrichment and detection steps and the markers used in these assays. We have focused on breast cancer as most clinical studies on CTC detection so far have been done in these patients.

Epithelial molecular markers in the peripheral blood of patients with colorectal cancer

Despite the modest improvements in patient survival from colorectal cancer in the last few decades, the overall five-year survival rate remains at 40 to 45 percent. Surgical resection is the mainstay of treatment for colorectal cancer; however, nearly one-half of all patients who undergo a potentially curative resection will relapse because of undetected micrometastasis. The fact that the overall survival rate remains poor strongly suggests that the dissemination of these cells occurs early in the disease process and emphasizes the need for finding feasible diagnostic methods with sufficient sensitivity and specificity. The most commonly used technique for the detection of nucleic acid material of disseminated tumor cells is the polymerase chain reaction. We critically review the literature on DNA and messenger ribonucleic acid molecular markers that have been used for the detection of circulating tumor cells in the peripheral blood of patients with colorectal cancer and other solid tumors as appropriate for comparison. The cytokeratins, particularly cytokeratin 19 and cytokeratin 20, are the most investigated prognostic markers, but even for these questions remain about their clinical value, and hence most recent studies are utilizing a combination of factors. There is an urgent need for standardized isolation and analysis techniques to be adopted thus allowing large-scale, appropriately controlled, multicenter trials to be undertaken on the most promising candidate markers.

Quantitative detection of circulating epithelial cells by Q-RT-PCR

INTRODUCTION

It has been shown that the quantity of circulating tumor cells (CTCs) in breast cancer patients is an independent predictor of survival and treatment response. Real time quantitative reverse transcriptase PCR (Q-RT-PCR) is a sensitive technique for detection of CTCs. Our aim was to investigate whether the technique can be used also to quantitate these CTCs.

METHODS

We tested cytokeratin 19 (CK19), maspin, mammaglobin, GAPDH and RPL19 genes for their level of expression and linearity of amplification in serial dilutions of RNA extracted from the MDA-MB-231, UACC-812, T47D and HS578T breast cancer cell lines. To simulate CTCs, serial dilutions of cultured T47D and HS578T cells were added to peripheral blood from healthy volunteers. The samples were subjected to enrichment, RNA extraction and Q-RT-PCR.

RESULTS

CK19 was reliably expressed in all four cell lines with a linear relationship between the quantity of added cells and the amount of CK19 RNA. The lower limit of reliable detection was 5 cells per sample, which corresponds to a concentration of 0.7 cell/ml in 7.5 ml of blood or would translate to a lower CTC concentration in a larger volume of blood.

CONCLUSION

This technique may prove useful for high throughput comparative quantification of CTCs in individual patients during treatment and subsequent follow up for research and clinical management purposes.

Multimarker RT-PCR assay for the detection of minimal residual disease in sentinel lymph nodes of breast cancer patients

The presence of metastases in lymph nodes is the most powerful prognostic factor in breast cancer patients. Routine histological examination of lymph nodes has limited sensitivity for the detection of breast cancer metastases. The aim of the present study was to develop a multimarker reverse transcriptase-polymerase chain reaction (RT-PCR) assay for the detection of minimal residual disease in sentinel nodes of breast cancer patients. RNA was extracted from 30 sentinel lymph nodes (SLN) obtained from 28 patients, three primary breast cancers (positive controls), three lymph nodes from patients with benign diseases, and peripheral blood lymphocytes of 10 healthy volunteers (negative controls). RT-PCR was performed using the following markers; cytokeratin (CK)-19, NY-BR-1 and mammaglobin B. RT-PCR results were compared to enhanced histopathologic examination and immunohistochemistry (IHC). All three positive controls showed strong PCR amplification for all three markers. None of the 13 negative controls was amplified by any of the three markers. Among the 30 SLN analysed, breast cancer metastases were detected in six SLNs by routine histology, in eight by IHC and in 15 by RT-PCR. We conclude that a multimarker RT-PCR assay probing for NY-BR-1, mammaglobin-B, and CK-19 is more sensitive compared to enhanced pathologic examination. This method may prove to be of value in breast cancer staging and prognosis evaluation.

Immunocytochemical detection of epithelial cells in the bone marrow of primary breast cancer patients: a meta-analysis

PURPOSE

The immunocytochemical detection of epithelial cells in the bone marrow (BM) of breast cancer (BC) patients has been shown to have prognostic importance in several studies. We conducted a systematic review of the literature and a meta-analysis to assess the specificity, rate of positivity and correlation with known prognostic variables as well as with disease free (DFS) and overall survival (OS).

DESIGN

We performed a systematic review from the published literature. We included studies with at least 20 previously untreated BC patients as well as non-BC controls that evaluated the presence of epithelial cells in BM using immunocytochemistry (IC).

RESULTS

We identified 14 eligible studies with 3253 BC patients and 532 controls. Our results showed that IC has an overall rate of positivity of 31% (95% CI: 30-33%), and specificity of 96% (compared to normal patients) (95% CI: 0.94-0.98). We observed significant direct correlations between IC BM positivity and the primary tumor's presence with expression of estrogen receptors, larger size and higher histologic grade as well as with the presence of more than 3 positive axillary lymph nodes. At 5 years of follow up IC positivity correlated directly with a lower DFS (relative risk=1.60; 95% CI: 1.39-1.83) and OS (relative risk=1.73; 95% CI: 1.29-2.31). The prognostic impact of BM positivity seemed to decrease with time.

CONCLUSIONS

We conclude that the finding of epithelial cells in BM of BC patients correlates with several known prognostic factors and has adverse impact in the DFS and OS of these patients that seems, however, to decrease with time.

The detection of circulating breast cancer cells in blood

At present, sampling of the lymph nodes or bone marrow for the detection of regions of metastatic disease in patients with breast cancer can only be undertaken at the time of initial diagnosis and surgery. However, the sampling of these tissues and the methods used are inaccurate, time consuming, and cannot be used for easy routine screening to determine disease recurrence and response to treatment. Because of the problems encountered with current methods and tissues sampled at the time of breast cancer diagnosis, this review discusses the urgent requirement for and potential development of a quick, simple, and accurate diagnostic test utilising the haematogenous system, a source of circulating tumour cells in patients with breast cancer, and highly sensitive molecular biological techniques, such as reverse transcription polymerase chain reaction. In addition, this review also highlights potential problems that may be encountered and should be avoided when devising such a test.

Circulating tumour cells in breast cancer

By use of modern immunological and molecular analytical techniques, cells with the characteristics of tumour cells can be detected in the blood of many patients with breast cancer. The ability to detect and characterise such cells routinely could have a profound influence on the early diagnosis of breast cancer, risk stratification in the adjuvant setting, early detection of relapse, and the development of new targeted strategies. In this review we discuss current techniques to detect circulating breast-cancer cells and the limitations of these approaches. We also review the clinical studies in breast cancer and discuss the potential relevance of this research to the future management of the disorder.

Peripheral blood c-erbB-2 expression by reverse transcriptase-polymerase chain reaction in breast cancer patients receiving chemotherapy

Minimal residual disease (MRD) evaluation in breast cancer patients is a promising tool to improve current staging procedures. In a previous work employing a CK-19-based reverse transcriptase-polymerase chain reaction (RT-PCR) technique for MRD detection, we identified a group of women who exhibited persistent negativity for this assay and for whom this technique was considered noninformative. In order to improve the yield of MRD detection in these patients, we evaluated the usefulness of RT-PCR detection of c-erbB-2 expression. We were able to detect up to 1 MCF-7 cell (positive for c-erbB-2 expression) in a mixture of 1,000,000 CCRF-CEM cells (negative for c-erbB-2 expression). We evaluated the specificity of this technique in the peripheral-blood mononuclear cells (PBMCs) of 20 healthy women and found that 2 of these women were positive for c-erbB-2 expression. In the PBMCs of a group of 16 women with breast cancer, 25% of the samples were positive for c-erbB-2 expression before chemotherapy. Except for race (P = 0.017), no other significant correlations were found, including c-erbB-2 expression in the primary tumor by immunoperoxidase. Interestingly, in the subgroup of 6 patients for whom this technique was informative, we found that 80% of the samples obtained while on chemotherapy were negative compared to only 10% obtained off treatment (P = 0.017). Additionally, 2 patients for whom CK-19 expression was noninformative had at least 1 c-erbB-2-positive sample. We conclude that this technique might be useful for MRD detection in breast cancer patients, but further studies are necessary to confirm our findings.