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CAR T Cells: Eliminating Residual Tumor Cells

By Jasmine Biju

According to the Perelman School of Medicine at the University of Pennsylvania, Chimeric Antigen Receptor(CAR) T Cell therapy may help to increase the efficacy of the surgery of a solid tumor. CAR T cell therapy is a treatment in which a patient’s T cells are ‘reprogrammed’ to attack cancer cells. Scientists grow large quantities of CAR T Cells to infuse in the patient, promoting the elimination of tumor cells missed by surgery.

T Cells are a type of white blood cell that helps with the body’s immune response. T cells specialize in targeting a specific antigen, a harmful substance foreign to the body, and activates only when it encounters this antigen. T Cells work by binding their receptor to an antigen-presenting cell, which essentially triggers two responses: the stimulation of B cells to make antibodies or the elimination of infected cells. This process occurs in adaptive immunity. Sometimes, the immune system fails to recognize antigens from cancer cells. So, T cells may remain inactivated.

CAR T Cell therapy has three steps: collecting T cells, engineering T cells, and infusing the CAR T cells. In this process, blood is drawn from the patient and flows into an apheresis machine which isolates the T cells. Scientists use these T cells to add a manufactured Chimeric Antigen Receptor. These CAR T cells begin to replicate and grow. When the quantity is sufficient, CAR T cells are injected into the patient’s arm. The CAR T cell targets tumor cells.

In a study published by Science Advances, the research involved the effects of CAR T Cells on post-partial tumor surgery of mice. Scientists engineered CAR T cells to target mesothelin, a surface marker of cancerous cells. In the control experiment that did not utilize the CAR T cell treatment, tumor growth in the mice increased resulting in death within seven weeks. On the other hand, in the experiment that utilized the CAR T cell treatment, remaining tumor cells disappeared in 19 of 20 mice, allowing them to survive without adverse effects. The results indicate that the surviving mice would not have to encounter tumor recurrence, which occurs when the procedure fails to eliminate all tumor cells.

For a solid cancer tumor, surgery can be sufficient. However, in

less-straightforward cases involving a lack of distinction between healthy tissue and tumor, the residual of microscopic tumor cells is fairly common. As proposed by researchers at the University of Pennsylvania, immediately applying CAR T cells after surgery enhances the effectiveness of the procedure and minimizes the possibility of the existence of residual cancer cells.

CAR T cells are altered by scientists to target proteins found in tumor cells. Currently, the FDA has approved six CAR T cell therapies utilized to target various hematological cancers such as leukemia, lymphoma, and multiple myeloma. So far, it is difficult for CAR T cells to target solid masses of tumors for its anti-immunity properties, however, this treatment is proven effective in executing the task of killing remaining cancer cells after surgery.

CAR T cell treatment in most cases is efficacious in minimizing the quantity of residual cancer cells to zero. Essentially, this additional therapy aids in providing hope to patients who do not possess conventional options. By lowering the risk of tumor recurrence, this treatment prevents patients from having to engage in numerous surgeries to eliminate the tumor.


  1. “Car T Cell Therapy.” National Cancer Institute.

  2. “T-cell Transfer Therapy.” National Cancer Institute, 2022.

  3. “Car T Cell Therapy.” Penn Medicine.

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