Chinese Scientists Find That Bacteria Can Promote Cancer Cell Metastasis
On April 8, 2022, Professor Cai Shang's group at the School of Life Sciences, Westlake University, China, published a paper in the internationally authoritative journal Cell, once again confirming the existence of bacteria inside tumor cells and demonstrating for the first time that bacteria unique to tumor cells in breast cancer patients play a key role in tumor metastasis.
In this study, Dr. Cai Shang and colleagues built a cohort of breast cancer model mice whose cancerous tissue was filled with large numbers of bacteria, closely resembling what is observed in human breast cancer. The number of bacteria in breast cancer tissue was about ten times that in normal breast tissue, and most of these bacteria colonized the cytosol of the cancer cells—that is, inside the cells. These intratumoral bacteria were even alive, and would gradually die in an antibiotic-permeable cell environment.
This study offers a new approach to cancer treatment. Dr. Cai's team found through experiments that after mice received combination antibiotic treatment, although the primary tumors did not shrink, metastatic tumors were markedly reduced. At the same time, if the tumor microbiota from peripheral blood was re-infused into tumor-bearing mice, the growth of orthotopic tumors was not greatly affected, but the level of tumor metastasis rose significantly. The mechanism may be that these tumor-associated bacteria have established a symbiotic relationship with cancer cells, specifically helping the cancer cells resist mechanical stress and promoting their passage through the bloodstream to achieve metastasis.
Antibiotics have positive significance in the treatment of tumor patients. Currently many tumor patients are treated with antibiotics while undergoing chemotherapy. Most TCM heat-clearing and detoxifying medicines have broad-spectrum antimicrobial effects, and clinically, TCM formulas focused on heat-clearing and detoxifying do indeed prolong patient survival. Dr. Cai's team's research provides a reasonable explanation for the TCM heat-clearing and detoxifying method in treating tumors.
Ancient Chinese doctors discovered long ago that leukemia and tumors are related to "heat-toxin." Therefore, when TCM treats such diseases, it mostly uses high doses of heat-clearing and detoxifying medicines, combined with toxin-attacking-toxin and blood-activating and stasis-resolving herbs, to achieve a synergistic anticancer effect. Of course, not all cancer patients are suitable for heat-clearing and detoxifying medicines; using them in patients without heat-toxin will backfire.
Tumors are diseases with very complex etiology and pathology. Once human cells become cancerous and form a tumor, it is difficult to reverse the process with a single method. Discovering the existence of intratumoral bacteria and their promotion of tumor cell metastasis is of great significance for clinicians. This research finding by Dr. Cai's team also deserves attention from contemporary TCM circles, as it will help us select formulas and medicines more precisely.