Culture and Characterization of Circulating Tumor Cells (CTC) in Melanoma and Other Cancers

A strong correlation has been established between CTC and the progression of breast, colon and prostate cancers. The number of CTC appears to act as a prognostic marker for relapse and survival in a number of epithelial cancers. Unfortunately, current CTC assays are not effective in reliably detecting circulating melanoma cells and the assay procedures damage cells prohibiting further study.

This study is designed to evaluate the sensitivity and specificity of the TrueCells assay, a novel approach to isolate and preserve cells for further research.

Primary Objectives:

• Evaluate feasibility and reproducibility of isolation of CTC using TrueCells technology.
• Optimize quantitative CTC recovery
• Provide preliminary data concerning correlation of these measurements with other methods of CTC recovery such as immunofluorescence, lipid-based staining.

Secondary Objectives:

• Explore correlation of immunofluorescent CTC assay and TrueCells CTC cultures with response to treatment by objective and immune response criteria, progression free survival, 1 and 2-year survival landmarks, and overall survival in cancer patients.
• Attempt to isolate long-term tumor cell lines for evaluation of somatic gene mutations, and gene and protein expression patterns related to individual tumors (not intended to identify familial or inherited mutations), and to test drug and biologic sensitivity.
• Isolate plasma RNA and DNA to assess expression tumor-specific markers (e.g., tyrosinase, B-FRAF, V600E, etc.) and metastasis-associated genes (e.g., MSH-1, thymidylate synthase, etc.).
• Perform ongoing developmental testing to continue to develop and optimize novel technical approaches to facilitate isolation of intact CTC.

Methods:

Blood samples will be collected from patients with melanoma (200), prostate cancer (200), other solid tumor cancers (up to 400), benign hematologic conditions (100), and healthy volunteers (up to 100). Sequential samples will be obtained from selected patients during disease progression or treatment response to allow exploration of potential correlation of CTC with response to treatment, progression-free survival and overall survival. Samples will be immediately de-identified and assigned a numerical code, dated and sent to TrueCells, LLC. Once donated, sample ownership passes to TrueCells, LLC.

Research studies include:

• CTC independently counted using immunofluorescent staining of thick smear prepared from entire buffy coat of two tubes of blood (tubes 1 & 2), stained with appropriate primary pan-tumor monoclonal antibody or lipid markers with confirmatory secondary antibodies to exclude inadvertent inclusion of leukocyte and endothelial subsets and verify recognition of the patient's cancer.
• Leukocytes (containing CTC) isolated by density gradient centrifugation. The buffy coat is plated into TrueCells proprietary cell culture medium and tumor cells grown and propagated (tubes 3 & 4). Cell colonies enumerated and compared to number of colonies identified by immunofluorescent staining.
• In some cases CTC may be able to be grown as long-term cell lines. These cells may be subject to further analysis such as evaluation of somatic gene mutations as well as gene and protein expression patterns to identify characteristics of individual tumors as well as drug and biologic agent sensitivity. There may be additional future in vitro experimental applications for these de-identified early-passage cell lines that have not yet been identified or anticipated in this application.
• Plasma (byproduct of leukocyte isolation process from tubes 3 & 4) will be collected and temporarily frozen for DNA and RNA isolation for molecular assays of melanoma molecular markers and metastatic gene expression. These samples are consumed in the assay procedure.

Clinical information will be abstracted from medical records and de-identified and stored in a password-protected spreadsheet. Information to be collected includes age, gender, T, N, M status, other health conditions, serum LDH, any specific tumor markers (e.g. PSA), circulating tumor cells (if analyzed by commercial assay), somatic genetic mutations present in cancer (e.g. B-RAF V600E in melanoma patients) mitotic rate of tumor, date of tumor diagnosis, treatment history, date of regional and metastatic progression and date of death (if applicable).

Inclusion criteria

• Diagnosis of melanoma, prostate cancer or other solid tumor malignancy; or benign hematologic disorder; or healthy volunteer.
• 18 years of age or older.
• Signed written informed consent.

Exclusion criteria