A systematic review examined how exercise-induced proteins called myokines affect cancer cells. These proteins include IL-6, SPARC, and irisin, which the body releases during physical activity. The analysis looked at existing research to understand their role in tumor growth and suppression.
The review found that several of these myokines can exert tumor-suppressive effects in laboratory settings. However, other myokines show functional duality, meaning they can either suppress or promote tumors depending on the specific microenvironmental context. This suggests the effects are not simple or one-sided.
Researchers noted that the majority of existing studies rely on in vitro cell models. These models lack validation in physiologically relevant in vivo settings or clinical contexts. Consequently, intracellular signaling pathways remain incompletely defined. Readers should be careful not to infer specific clinical outcomes from these lab models or assume defined pathways where they are not yet clear.