Researchers at Penn State have developed a promising new strategy that uses mixtures of bacteria-derived products—called microbial cocktails—to enhance the immune system’s ability to fight bladder cancer. Their findings, published in Nature Communications, show that these tailored bacterial mixtures significantly strengthen anti-cancer immune responses in patient tumor samples and mouse models. Moreover, the approach can be personalized while remaining cost-effective compared to many existing cancer therapies.
How Bacteria Power Immunotherapy
Lead author Pak Kin Wong, professor of biomedical engineering and mechanical engineering at Penn State, explained that immunotherapy remains one of the most powerful cancer treatments available. In bladder cancer, clinicians already use a bacteria-based method called Bacillus Calmette–Guérin (BCG) immunotherapy, introduced in 1976. This treatment involves placing live bacteria into the bladder to stimulate an immune attack on cancer cells.
However, Wong noted that BCG works only for a subset of patients. Although scientists recognized the link between bacterial infection and cancer regression as early as the 1800s, the therapy has not evolved much and continues to rely on a single bacterial strain. Since the human immune system interacts with thousands of bacterial types daily, Wong emphasized that exploring a broader range of bacteria could unlock far more effective immunotherapy options.
Creating Personalized Microbial Cocktails
To address these limitations, the research team introduced a novel approach: microbial product cocktail (MPC) immunotherapy. Instead of using whole live bacteria, MPC relies on microbial products extracted from bacteria. This method gives researchers greater control, reduces infection risk, and allows rapid testing of diverse bacterial combinations.
To determine the optimal cocktail for each patient, the researchers designed an artificial intelligence (AI) model that selects and doses microbial products based on predicted effectiveness. They tested these combinations on patient-derived tumor organoids. These are miniature tumors grown from the patient’s own cancer tissue. The goal was to evaluate how well each cocktail activated immune responses.
Integrating AI helps overcome the immense challenge posed by countless possible bacterial mixtures. With computational predictions, the team can identify the most promising microbial cocktails efficiently and tailor therapy to each patient’s tumor biology.
“By testing a small set of organoids in the lab, we can see how well a patient’s tumor recruits immune cells and which cocktail triggers the strongest reaction,” Wong said. “This allows us to quickly pinpoint the most effective treatment.”
Testing the Therapy and Looking Ahead
As reported by medicalxpress, the team validated their approach in mice with bladder cancer, the standard preclinical model for immunotherapy research. The personalized microbial cocktails more than doubled long-term survival rates compared to traditional BCG treatment. Additionally, tumors from MPC-treated mice showed stronger infiltration of cancer-fighting immune cells. This further proves the cocktail’s ability to improve immune activation.
Looking to the future, the researchers aim to refine their MPC strategy and expand it to other cancer types. Although the current work focuses on bladder cancer, Wong believes the underlying concept can be adapted broadly across oncology.
“We’re only beginning to explore what this approach can achieve,” Wong said. “As we continue developing MPC immunotherapy, we will understand more about how bacteria and the immune system interact and how to harness that relationship to treat cancer. Our ultimate goal is to create a safe, efficient, and personalized treatment option for patients worldwide.”