MIR21 and cancer: Given MIR21 is involved in the synthesis of numerous inflammatory cytokines such as IL-23 and IL-17A [49] in the colon mucosa, it is possible that a positive feedback loop involving MIR21 overexpression, synthesis of pro-inflammatory factors and activation of oncogenic pathways may also contribute to JAM-A inactivation and the downstream consequences on barrier function and cancer promotion.