Bacillus Calmette-Guerin (BCG) therapy is the main intravesical immunotherapy for treating early-stage bladder cancer. According to a study led by Spanish researchers, this bacterium activates the patient’s natural killer cells, which are ultimately responsible for killing off tumor cells. Understanding the mechanism of action of this therapy can help designing new protocols and customize the treatment of these cancers.

Although BCG therapy, also used as a vaccine for tuberculosis, has shown to be effective in 70% of patients with bladder cancer, to date it was not known how it exerted its antitumor effect. Now, a study published in the scientific journal Oncoimmunology reveals the mechanism through which this therapy increases the ability of certain immune cells to recognize tumor cells and kill them.

“It is important to know how BCG therapy works against bladder cancer because, despite the good results of this treatment, some patients have to leave it because of adverse effects caused by the introduction of a live bacterium into the bladder, such as stinging and irritation,” explains Mar Valés, lead author of the work and researcher at the National Center for Biotechnology (CNB-CSIC) in Spain.

“Deeply understanding the mechanism of action through which the bacterium exerts its antitumor action opens the door for the design of new protocols that reduce side effects and increase the ability of natural killer cells to kill tumors” , Valés adds.

Activating immune system cells to recognize and fight against cancer is a strategy known as immunotherapy. Currently, by the scientific community around the world has focus their studies in this type of therapy as it has shown successful as anti-tumor therapy. However, several decades ago, bladder cancer was treated by introducing BCG directly into this organ. The bacterium activates the local immune response that favors the elimination of the tumor.

“At present we have begun a new investigation with the intention of avoiding the adverse effects that are often associated with this therapy. We want to find ways to activate natural killer cells using fragments of the bacterium and soluble immunological factors instead of the whole bacteria,” Valés concluded.

 

Source: Agencia SINC