Genotype/phenotype analyses of low frequency tumor cells using computerize image microscopy

Combination DNA/RNA FISH and immunophenotyping

This unit presents methods for combining immunophenotyping with DNA/RNA FISH. The approach is used in so-called genotype/phenotype analysis to identify chromosomal aberrations in sub-populations of cells present in heterogenous populations. Combining RNA and DNA detection with identification of cellular proteins is quite difficult. This series of protocols is provided to enable the successful application of the combination of these techniques.

Combination of quantification and observation methods for study of “Side Population” cells in their “in vitro” microenvironment

BACKGROUND

Qualitative and quantitative analyses of the rare phenotypic variants in in vitro culture systems is necessary for the understanding of cell differentiation in cell culture of primary cells or cell lines. Slide-based cytometry combines image acquisition and data treatment, and associates the power of flow cytometry (FCM) and the resolution of the microscopic studies making it suitable for the analysis of cells with rare phenotype. In this paper we develop a method that applies these principles to a particularly hot problem in cell biology, the study of stem cell like cells in cultures of primary cells, cancer cells, and various cell lines.

METHODS

The adherent cells were labeled by the fluorescent dye Hoechst 33342. The images of cell populations were collected by a two-photon microscope and processed by a software developed by us. The software allows the automated segmentation of the nuclei in a very dense cell environment, the measurement of the fluorescence intensity of each nucleus and the recording of their position in the plate. The cells with a given fluorescence intensity can then be located easily on the recorded image of the culture plate for further analysis.

RESULTS

The potential of our method is illustrated by the identification and localization of SP cells in the cultures of the C2C12 cell line. Although these cells represent only about 1% of the total population as calculated by flow cytometry, they can be identified in the culture plate with high precision by microscopy.

CONCLUSION

Cells with the rare stem-cell like phenotype can be efficiently identified in the undisturbed cultures. Since the fluorescence intensity of rare events and the position of thousands of surrounding cells are recorded at the same time, the method associates the advantage of the FCM analysis and the microscopic observation.

Methods for isolating circulating epithelial cells and criteria for their classification as carcinoma cells

Novel assay methods developed for the isolation and characterization of circulating tumor cells (CTC) of epithelial origin offer the potential of markers for the non-invasive gathering of clinical information relevant to the diagnosis, evolution and treatment of carcinoma. Of the numerous techniques currently used to analyze CTC, slide-based assays are perhaps the most common. While traditional combined immunocytochemical/brightfield microscopy systems continue to be the most frequently employed, fluorescence-based analysis is gaining in importance. This is partly because fluorescence microscopy analysis of slide-mounted CTC can provide simultaneously cytogenetic as well as morphologic and multiple phenotypic information. In particular, fluorescence microscopy analysis of slide-mounted CTC can accurately determine genetic changes at the chromosomal level in patients with recurrent disease. More importantly, by identifying genetic aberrations in CTC, it becomes possible to choose those patients most likely to benefit from a given treatment. The potential of this technique has already been demonstrated by employing fluorescence in situ hybridization (FISH) methods to measure expression of the HER2/neu gene in tissue from patients with breast carcinoma for the specific purpose of identifying those patients most likely to respond to Trastuzumab targeted therapy. Here, we review the major methodologies used in the preparation and analysis of the slide-based assays.

Circulating tumor cells in patients with breast cancer dormancy

PURPOSE

The purpose of this study was to test the hypothesis that circulating tumor cells (CTCs) are present in patients many years after mastectomy without evidence of disease and that these CTCs are shed from persisting tumor in patients with breast cancer dormancy.

EXPERIMENTAL DESIGN

We searched for CTCs in 36 dormancy candidate patients and 26 age-matched controls using stringent criteria for cytomorphology, immunophenotype, and aneusomy.

RESULTS

Thirteen of 36 dormancy candidates, 7 to 22 years after mastectomy and without evidence of clinical disease, had CTCs, usually on more than one occasion. Only 1 of 26 controls had a possible CTC (no aneusomy). The statistical difference of these two distributions was significant (exact P = 0.0043). The CTCs in patients whose primary breast cancer was just removed had a half-life measured in 1 to 2.4 hours.

CONCLUSIONS

The CTCs that are dying must be replenished every few hours by replicating tumor cells somewhere in the tissues. Hence, there appears to be a balance between tumor replication and cell death for as long as 22 years in dormancy candidates. We conclude that this is one mechanism underlying tumor dormancy.

Peripheral blood circulating cytokeratin-19 mRNA-positive cells after the completion of adjuvant chemotherapy in patients with operable breast cancer

BACKGROUND

The purpose of this study was to evaluate the prognostic significance of the molecular detection of cytokeratin 19 (CK-19) mRNA-positive cells in the peripheral blood of women with operable breast cancer after the completion of adjuvant chemotherapy.

PATIENTS AND METHODS

Blood from 161 patients with stage I and II breast cancer, obtained after the completion of adjuvant chemotherapy, was tested by nested RT-PCR for CK-19 mRNA detection. Using univariate and multivariate analyses possible interactions with other prognostic factors and association of CK-19 mRNA detection with risk of relapse, disease-free interval (DFI) and overall survival were investigated.

RESULTS

After completion of adjuvant chemotherapy, 27.3% of patients had peripheral blood CK-19 mRNA-positive cells; there was no association of this finding with any other prognostic factors or the type of chemotherapy regimen used. For patients with less than four involved axillary lymph nodes the risk of relapse was 3.81 [95% confidence interval (CI) 1.06-13.71] times higher, and the DFI was significantly reduced (P = 0.028) if CK-19 mRNA-positive cells were detectable in the blood after the completion of adjuvant chemotherapy. In contrast, for patients with four or more involved lymph nodes, the presence of CK-19 mRNA-positive cells after adjuvant chemotherapy did not significantly affect the risk of relapse or DFI. Furthermore, the risk of relapse was higher (hazards ratio 3.70; 95% CI 1.09-13.89) and the DFI was reduced (P = 0.022) for patients with detectable CK-19 mRNA-positive cells following adjuvant cyclophosphamide, methotrexate and 5-fluorouracil (CMF) as compared with epirubicin, cyclophosphamide and 5-fluorouracil (FEC) or sequential taxotere-epirubicin and cyclophosphamide (T/EC) chemotherapy.

CONCLUSIONS

The detection of CK-19 mRNA-positive cells in the peripheral blood after adjuvant chemotherapy may be of clinical relevance for patients with early breast cancer and less than four involved axillary lymph nodes.

Recent development on computer aided tissue engineering--a review

The utilization of computer-aided technologies in tissue engineering has evolved in the development of a new field of computer-aided tissue engineering (CATE). This article reviews recent development and application of enabling computer technology, imaging technology, computer-aided design and computer-aided manufacturing (CAD and CAM), and rapid prototyping (RP) technology in tissue engineering, particularly, in computer-aided tissue anatomical modeling, three-dimensional (3-D) anatomy visualization and 3-D reconstruction, CAD-based anatomical modeling, computer-aided tissue classification, computer-aided tissue implantation and prototype modeling assisted surgical planning and reconstruction.

Minimal residual disease in gastrointestinal cancer

Tumor progression after curative resection of gastrointestinal carcinomas is probably caused by pre- or intraoperative tumor cell dissemination. Disseminated tumor cells are generally detected by immunohistochemistry- or PCR-based molecular-biology methods. A consensus on which is the most adequate detection method has not yet been found, which makes the comparison of data difficult. The prognostic relevance of disseminated cells has been shown, at least in part, for esophageal, gastric, pancreatic, and colonic cancer. The data regarding hepatocellular cancer is conflicting. This article gives a critical review of tumor cell detection in gastrointestinal cancer.

Detection and clinical importance of micrometastatic disease

Metastatic relapse in patients with solid tumors is caused by systemic preoperative or perioperative dissemination of tumor cells. The presence of individual tumor cells in bone marrow and in peripheral blood can be detected by immunologic or molecular methods and is being regarded increasingly as a clinically relevant prognostic factor. Because the goal of adjuvant therapy is the eradication of occult micrometastatic tumor cells before metastatic disease becomes clinically evident, the early detection of micrometastases could identify the patients who are most (and least) likely to benefit from adjuvant therapy. In addition, more sensitive methods for detecting such cells should increase knowledge about the biologic mechanisms of metastasis and improve the diagnosis and treatment of micrometastatic disease. In contrast to solid metastatic tumors, micrometastatic tumor cells are appropriate targets for intravenously applied agents because macromolecules and immunocompetent effector cells should have access to the tumor cells. Because the majority of micrometastatic tumor cells may be nonproliferative (G0 phase), standard cytotoxic chemotherapies aimed at proliferating cells may be less effective, which might explain, in part, the failure of chemotherapy. Thus, adjuvant therapies that are aimed at dividing and quiescent cells, such as antibody-based therapies, are of considerable interest. From a literature search that used the databases MEDLINE(R), CANCERLIT(R), Biosis(R), Embase(R), and SciSearch(R), we discuss the current state of research on minimal residual cancer in patients with epithelial tumors and the diagnostic and clinical implications of these findings.