Natural bacteria destroys cancer

Recently, a bacteria has been found in  frogs in Japan that destroys cancer in one dose. While this might sound like science fiction, it's a real and historically rooted area of cancer research. The concept is simple: certain bacteria have an innate ability to seek out and thrive in tumors, where they can then attack the cancer directly and stimulate the body's immune system to fight it.
This field, known as bacterial or oncolytic bacterial therapy, has progressed from early observations to modern clinical trials. Here’s how it works and what's happening in the field today.

How Bacteria "Naturally" Destroy Cancer
Bacteria possess several unique traits that make them promising anticancer agents. Their effectiveness comes from a combination of several key mechanisms:

Inherent Tumor Targeting: Tumors have a unique environment—they are often low in oxygen (hypoxic), acidic, and have a chaotic blood supply. This is an ideal environment for many bacteria. Facultative anaerobes (like Salmonella) and obligate anaerobes (like Clostridium) can specifically target, colonize, and proliferate within these tumor sites while largely avoiding healthy tissues.

Direct Tumor Lysis: Some bacteria, such as Photobacterium angustum and certain Clostridium species, can directly kill cancer cells. For instance, Clostridium can release toxins that damage cancer cell membranes, and research has shown P. angustum has an "intrinsic oncolytic activity" that contributes to direct tumor lysis.
Immune System Activation: This is perhaps the most powerful mechanism. Bacteria are rich in molecules called pathogen-associated molecular patterns (PAMPs), such as lipopolysaccharides (LPS). When bacteria colonize a tumor, these PAMPs act as a powerful signal to the immune system, triggering an intense and targeted immune response against the tumor. This is the same principle behind Bacillus Calmette-Guérin (BCG), a vaccine for tuberculosis that is now an FDA-approved standard treatment for non-muscle invasive bladder cancer.

The Modern Frontier: Engineering for Precision
While "natural" bacteria are effective, their potency can be limited or unpredictable. Today, scientists use genetic engineering to create even more powerful and safer "designer" bacteria. This approach has several advantages:
Enhanced Safety: Harmful genes are removed to create "attenuated" strains that are safe for patients but still effective.
Targeted Payload Delivery: Engineered bacteria can be programmed to deliver therapeutic payloads directly to the tumor, such as:
Cytokines (like IL-2) that boost the immune response.
Prodrug-converting enzymes that activate chemotherapy drugs only within the tumor, reducing systemic side effects.
Tumor antigens to train the immune system to recognize and attack cancer cells.

Programmable Control: Using synthetic biology, bacteria are equipped with genetic circuits that can sense the tumor environment and release their payload only at the right time and place.
 

Promising Bacteria in Research and Clinical Trials
This is not just a laboratory concept. Several bacteria strains are currently being studied or are in clinical trials for various cancers. Here are some key examples:
Bacterial Strain
Key Mechanism / Approach

Cancer Types
Status / Phase
Salmonella typhimurium (e.g., VNP20009)
Tumor targeting, immune activation, and drug delivery
Advanced solid tumors, metastatic pancreatic cancer
Clinical Trials (Phase I/II)
Clostridium novyi-NT
Obligate anaerobe that colonizes tumor hypoxic zones, causing tumor lysis and immune response
Refractory solid tumors
Clinical Trials (Phase I)
Listeria monocytogenes (e.g., CRS-207, ADXS11-001)
Infects and kills cancer cells, activates strong T-cell responses
Pancreatic, cervical, lung cancer, mesothelioma
Clinical Trials (Phase I/II/III)
Bifidobacterium longum
Probiotic that thrives in hypoxic tumors
Advanced solid tumors

Clinical Trials (Phase I/II)
Photobacterium angustum
A naturally marine bacterium with strong tumor tropism and direct oncolytic activity
Colorectal cancer (preclinical)
Preclinical
Escherichia coli Nissle 1917 (e.g., SYNB1891)
Engineered probiotic for intratumoral injection; stimulates STING pathway
Advanced solid tumors, lymphoma
Clinical Trials (Phase I)
Proteus mirabilis (PM) & Rhodopseudomonas palustris (RP)
A bacterial consortium with strong immunogenic oncolytic efficacy
Colorectal, sarcoma, lung, breast cancer (preclinical)
 

Preclinical

A note on clinical trials: While early studies have shown these therapies are feasible and have manageable side effects in some cases, many natural and engineered strains in early-stage trials have shown limited efficacy as a monotherapy. This highlights that the field is still in its early stages, but it also points to the next steps, like combining bacterial therapy with other treatments like checkpoint inhibitors to unlock its full potential.
We hope this takes place soon to save the lives of many patients.

By Jamuna Rangachari