January 7, 2020 (ScienceDaily)
Many patients with malignant tumors have tumors that are “cold,” meaning the tumors do not contain many immune cells, or they have cells that block the immune system from intervening and fighting invaders. If somehow immune cells could be increased within a tumor, it could change from “cold” to “hot” and allow it to be more recognizable by the immune system. Research shows that patients with “hot” tumors have better response rates to treatments and improved survival outcomes.
Recently, physicians and scientists at Rush University Medical Center discovered when injected into tumors, flu vaccines turned them from “cold” to “hot.” This finding could potentially lead to the development of a new immunotherapy for the treatment of cancer.
It was found, using a National Cancer Institute database, that people with lung cancer who were hospitalized for a lung infection from the flu at the same time, lived longer that those who had lung cancer with no flu. A similar outcome was seen in mice with tumors and a flu lung infection.
Since not a lot is known about this effect on live vaccines, the researchers inactivated the flu virus, and basically created a flu vaccine. When injected into mice with melanoma, tumors grew slower or shrunk, and the injection made tumors “hot” by increasing dendritic cells. This also increased cells known as CD8+ T cells which have the innate ability to detect and kill tumor cells. This was not only observed in mouse models of skin melanoma but also, in models of metastatic triple-negative breast cancer.
Next, the researchers wanted to test how malignant tumors would respond to FDA-approved flu vaccines being that lab-created flu vaccines were so successful. Sure enough, injection of the FDA-approved flu shots also resulted in reduced tumor growth.