TLR2 and cancer: The relationship between certain streptococci and carcinogenesis has been known for many years.214 For instance, Coley’s toxins, an early form of cancer immunotherapy, were based on Streptococcus pyogenes (S. pyogenes).215 In recent studies, the metabolites of S. pyogenes were examined, revealed that S. pyogenes acted as an agonist of the TLR2-TLR1 signaling pathway, displaying a 6 μM EC50 (median effect concentration).