It is appealing to identify biobehavioral relationships and their mechanisms in order to identify more objective measures of efficacy. This overview focuses on studies that have used these immune and endocrine measures to evaluate MBSR on key body systems known to play a role in cancer prevention and progression. This may benefit future study designs for higher levels of evidence and to identify knowledge gaps regarding the effectiveness of MBSR. This enhances the possibility of implementing MBSR training more widely and effectively in cancer care settings.