A tumor with metastases that regressed following vaccination against Covid-19. This is what happened to a 61-year-old woman in the United States and as reported by a group of researchers from the MD Anderson Cancer Center in Houston in a study published in the "Journal for Immunotherapy of Cancer".

According to the scholars, the woman had been affected by a tumor of the salivary glands, and after the removal surgery and radiotherapy had highlighted the presence of lung metastases in the CT scan, an element that suggested an irreversible course of the disease.

The pulmonary nodule mass had doubled in six months from 1.4 to 3 centimeters, to the point that doctors considered opting for a clinical trial. Before starting it, however, the patient was subjected to two doses of the anti-Covid Moderna vaccine to protect her from the risks of the pandemic given her immunosuppressed condition. And here is the unexpected evolution: after the vaccine, Tacs have shown a progressive reduction of lesions and a change in the composition of the tumor tissue enriched within it by cells of the immune system (B lymphocytes, T lymphocytes, dendritic cells and natural killer) .

According to doctors, "the intense inflammatory response stimulated by the vaccine may have promoted an anticancer response."

The experts led by Renata Ferrarotto, director of the head and neck cancer oncology department of the MD Anderson Cancer Center, also highlighted the "significant reduction in the absolute number of cancer cells and the fraction of them that actively proliferated" .

The key to what happened could be T lymphocytes, a type of white blood cell involved in the defense against Covid and in immunotherapy against cancer. The increase in this type of cell after vaccination - and before tumor shrinkage - is a sign of the body's response to vaccination and at the same time could be an explanation for what is observed in cancer reduction.

In the patient's case, the mRna vaccine could, therefore, have awakened the immune system that identified the lung metastases and fought them, as evidenced by the presence of lymphocytes and other immune cells in the metastases.