Bioassay for quantitating circulating tumor cells in a syngeneic mouse tumor system

Area of Science:

• Oncology
• Immunology
• Surgical Oncology

Background:

• Quantifying circulating tumor cells (CTCs) is crucial for cancer staging and treatment monitoring.
• Existing methods for CTC detection and enumeration have limitations.
• A reliable bioassay is needed to assess tumor cell dissemination in vivo.

Purpose of the Study:

• To develop and optimize a bioassay for quantifying tumor cells in blood specimens.
• To investigate factors influencing tumor cell dissemination in a syngeneic mouse model.
• To correlate CTC levels with regional lymph node metastasis.

Main Methods:

• A bioassay involving intramuscular injection of blood containing tumor cells into recipient mice.
• Calculation of a tumor index based on tumor takes and size.
• Histological examination for regional node metastasis.
• Manipulation of primary tumors (surgical removal, ligation, trauma) and immune status (immunosuppression, immunostimulation).

Main Results:

• The bioassay successfully quantified tumor cells in venous blood.
• Surgical removal, ischemia, and trauma of the primary tumor increased CTCs and regional node metastasis.
• Repeated physical trauma increased CTCs but not node metastasis.
• Immunosuppression enhanced CTC dissemination, while immunostimulation reduced it.

Conclusions:

• The developed bioassay is effective for quantifying CTCs in vivo.
• Primary tumor manipulation and host immune status significantly impact tumor cell dissemination.
• Findings highlight the complex interplay between primary tumor burden, local interventions, and systemic tumor spread.