It is well-known that the immune system has the capability to eradicate many types of cancer, especially highly sensitive cancers such as renal cell carcinoma and the skin cancers called melanomas.

A study has shown that a person’s ability to utilize anticancer immunity depends heavily on certain probiotics. Certain strains of experimental mice have been shown to powerfully suppress the growth of implanted melanomas; other strains were unable to.

Therefore, in the latter type of mice the tumors became very aggressive.

Researchers found that if they took some of the feces from the powerful immune tumor-killing mice and implanted it in the colons of animals with the weak antitumor immunity, they could turn immune-deficient mice into tumor-killing animals.

What made the difference in the animals’ ability to kill the tumors was that the cancer-killing mice were able to stimulate T-lymphocytes to enter the tumor and kill the cancer cells. The mice with weaker immune systems could not do that.

Of all the colon bacteria within the stool of the cancer-killing mice, it was the Bifidobacteria that was specifically linked with this beneficial effect. That included several species, including B. breve and B. longum, both of which can be obtained in commercial probiotic products.

The researchers also discovered that to be effective, the bacteria had to be alive. Live bacteria stimulated the animals’ bodies to produce tumor-killing immune T-lymphocytes.

Further study found that the bifidobacteria was stimulating dendritic immune cells, which are critical for antitumor immunity.

These species of colon bacteria also enhanced other types of cancer treatments. This is good news for cancer patients and for those who have survived cancer, as immune surveillance is essential to keep the tumors from returning.

Other studies have found that Bacteroides species of bacteria also can enhance antitumor immunity, but that species is not commercially available.