Oncology

 The Importance of Circulating Tumor Cells

Accurate disease staging is the first step in cancer management. Many previously unmanageable cancers can now be treated with new therapies if detected in the early stage of the disease. The most significant are cases with metastatic disease, in which the primary tumor has spread to other organ sites, making treatment and management more complicated.  Therefore, clinical investigators believe that presence of circulating tumor cells (CTCs) in the blood is an indicator of metastasis.  Methods to recover and analyze such CTCs would enable non-invasive methods of evaluating individual patient’s response to therapy.  Studies confirm the presence and utility of circulating tumor cells as a surrogate for biopsy. [i]

Examples of Circulating Tumor Cells:

                                 Prostate                                   Breast                                   Ovarian

                                                                               CK+ / CD45- / DAPI +                                                   

The Value of Monitoring Tumor Cells

Response to therapy is patient dependent, some respond better than others.  In many cases, cells that are sensitive to chemotherapy initially die, but some cells within the tumor survive. These cells continue to grow and give rise to resistant tumors, [ii] in which the tumor is populated with more aggressive cells that are now resistant, even in the presence of chemotherapy. When relapse occurs, cancer cells continue to grow. Clinicians would value a diagnostic assay to enable frequent sampling of tumor cells during the course of treatment as means of measuring the affects of the drug.   Therapies could be modified as soon as possible to better manage the tumors’ growth and metastatic potential. Rapid and timely therapeutic intervention can increase the probability of tumor regression or even eradication. To monitor these changes, scientists and clinicians are compiling a list of biomarkers present within specific cancers. These are specific genes and proteins that are expressed by tumor cells and indicate how the tumor is responding to therapy.  There are also gene alterations and morphological aberrations that occur during apoptosis that could serve as potential biomarkers.

Examples of Apoptotic CTCs:

An Upsurge in New Molecular Diagnostic Assays

Research in many of major cancers, including breast, prostate and colorectal cancers, has led to better understanding of molecular pathways for which specific drugs are designed to alter or inhibit tumor growth. This has led to an upsurge in molecular diagnostics. Some investigators have proposed enumeration (counting) of circulating tumor cells (CTCs) in the blood as a biomarker of drug response. [iii]

The Power of Single Cell Capture and Analysis

The CEE™ technology permits enumeration as well as specific interrogation of tumor cells. Captured cells can be subjected to molecular cytogenetic testing (for example, FISH – fluorescent in situ hybridization) to detect chromosomal abnormalities, molecular staining to detect specific protein alterations (antibodies) as well as expression (RNA) analysis. In breast cancer, cell-based tests such as FISH for HER-2/neu oncogene are important, as is immunohistochemical staining. Such tests identify patients who will respond to estrogen-based therapy. [iv] In colorectal cancer, specific chromosome abnormalities and changes in programmed cell death are well defined. For example, modification of MLH1 expression is an indication of disease aggressiveness and is used to measure a drug’s effectiveness on tumor growth. [v] In prostate cancer, detection of fusion transcripts involving the TMPRSS gene is of great interest in identifying patients who are resistant to certain therapies.

Methods of Confirmation and Analysis on CEE Channel

FISH Analysis:

                   Breast Cancer CTC                      

Pan CK Label Antibody (Green, FITC)

Multi-Probe FISH for Chromosome Aneuploidy

H&E Staining (brightfield):

Ovarian  Cancer CTCs