The flu vaccine turns out to be a wonder weapon against cancer! US clinical trial directly injects tumors to help regression

The latest research attempts to inject influenza vaccine directly into tumors to observe whether it can trigger a local immune response; situational photo. (AP)

[Compiled by Chen Chengliang/Comprehensive Report] The vaccine usually used to prevent influenza was directly injected into skin cancer tumors and achieved effective results. Is this true? The Ohio State University Wexner Medical Center conducted a small clinical trial in which 18 melanoma patients received this experimental treatment. Seven of them showed signs of tumor regression, and three of them had no cancer cells in the surgically removed tissue.

The Washington Post reported that the preliminary research results were published at the annual meeting of the Society for Immunotherapy of Cancer (SITC) in Phoenix, USA, in November. The research team hopes to use the influenza vaccine to trigger an immune response within the tumor and attract more immune cells into the tumor.

The trial subjects were all patients with surgically removable melanoma. The researchers first administered a dose of influenza vaccine to the patient's arm, injected it directly into the tumor a few days later, and gave a second injection on the 12th day. The intratumoral injection dose received by most patients each time was about three times that of a regular influenza vaccine, and no one suffered serious side effects during the trial.

About two weeks after the second injection, doctors surgically removed the tumor and examined the tissue. They found that immune cells had entered most of the samples. Blood tests also observed changes in inflammatory signals and immunosuppressive cells.

Off-the-shelf flu vaccine injected into tumors to explore low-cost immunotherapy

Researchers speculate that the influenza vaccine may trigger an infection-like immune response in tumors, changing the tumor environment that originally suppresses immune cells and prompting more immune cells to enter and identify cancer cells.

This approach is different from personalized cancer vaccines. The latter must be tailored to the patient's tumor characteristics, while the influenza vaccine is an off-the-shelf product that does not need to be redesigned and has the potential to reduce treatment costs.

However, this trial only included 18 patients and had no control group. It is currently impossible to confirm whether the tumor regression is caused by the vaccine injection, and it is only applicable to tumors that can be injected directly with a needle.

A Danish research team conducted a similar experiment on 10 colorectal cancer patients through endoscopy. Although immune cells increased in the tumors, the tumors did not shrink significantly. The Ohio State team next plans to test whether combining immune checkpoint inhibitors with metastatic melanoma that cannot be surgically removed would help.