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Body’s own Cancer Defense
Context:
A study from Northwestern University in Chicago, published in The Journal of Clinical Investigation, found that white blood cells activated by severe COVID-19 can help combat cancer metastasis.
Potential Cancer Remission After COVID-19:
- There are rare reports of cancer going into remission after COVID-19 infection.
- A 2023 study found 16 cases of cancer remission (including leukemia, lymphoma, myeloma, and kidney cancer) following COVID-19, though it remains unclear if the infection directly caused the remission.
- Spontaneous cancer remission has been known to occur in certain cases, such as with neuroblastoma (a childhood tumour), possibly due to an activated immune system targeting cancer cells.
Historical Background and Evolution
- Coley’s Toxins: The idea of using the immune system against cancer dates back to the late 19th century with Dr. William Coley, who observed that bacterial infections could improve cancer outcomes.
- This concept laid the groundwork for modern immunotherapy treatments.
- Recent Immunotherapy Advances: A 2022 study demonstrated that immune checkpoint inhibitors could induce complete remission in rectal cancer patients without surgery.
- This was particularly effective for patients with mismatch repair-deficient (dMMR) rectal cancer, a condition that makes tumours more susceptible to immunotherapy.
- CAR-T Therapy: Involves reprogramming the patient’s own T cells to attack cancer. This approach is currently used for certain blood cancers like leukemia and lymphoma.
The Discovery:
- The study focused on a specialised type of white blood cell called induced non-classical monocytes (I-NCMs).
- These cells are activated by infections (like COVID-19) or chemicals and have unique properties that make them effective in targeting cancer cells.
- Mechanism of Action: I-NCMs have a unique receptor, CCR2, that helps them detect and migrate toward cancerous or inflamed tissues.
- Once at the tumour site, they call in natural killer (NK) cells, which are part of the body’s innate immune system and are effective in directly destroying abnormal cells like cancer cells.
Immunotherapy for Cancer:
- Immunotherapy has emerged as a promising cancer treatment by leveraging the body’s immune system to fight cancer.
- Cancer cells often evade detection by the immune system, and immunotherapy works to overcome this by boosting immune responses.
- Limitations: Not all cancers respond to immunotherapy, and some may develop resistance over time.
- The effectiveness of immune checkpoint inhibitors depends on factors like tumour microenvironment, mutations, and PD-L1 expression.
- The study highlights the potential of I-NCMs to assist in cancer treatment, adding to the broader field of immunotherapy. However Using chemicals to generate I-NCMs, such as mifamurtide, has had limited success in clinical trials for cancer.
Challenges:
- Tumour Microenvironment: Cancer cells can create an environment that suppresses immune responses, making it difficult for the immune system to attack them.
- Heterogeneity: Cancer cells can vary within a tumour and between different tumours, making it challenging for the immune system to target all cancer cells effectively.
Future Directions:
- Personalised Medicine: Tailoring immunotherapy treatments to individual patients based on their specific cancer characteristics.
- Combination Therapies: Immunology therapy can be used in combination with other treatments like chemotherapy, radiation, or targeted therapy to enhance effectiveness.
