Streptococcus pyogenes in tumor treatment: the past, present and future

Abstract

In light of the recent emergence of immunotherapy as a possible treatment in Oncology, and considering the concept of spontaneous tumor regression following an infectious episode, the present work aimed to understand the role of infectious diseases in tumor treatment, specifically concerning the pathogen Streptococcus pyogenes. The pertinence of this bacteria in cancer treatment has been investigated throughout the last century and has achieved promising results, but it still isn't a reliable tool. This work reviews the most relevant aspects of Streptococcus pyogenes usage in cancer treatment, including: Streptococcus pyogenes-based formulations, administration protocols used, possible mechanisms of action for the evidenced tumor regression, main side effects observed and possibilities for clinical assessment of responders and non-responders, as well as the most relevant differences in the outcomes observed in different clinical studies. The current evidence suggests that Streptococcus pyogenes has established itself as a reliable inducer of the immune system, which can positively contribute to cancer treatment. However, further clinical evaluations are still needed to validate the present findings and allow for a conclusion to be drawn.