CD40LG and carcinoma: However, in CD40 + carcinomas, CD40 ligation via mCD40L but not sCD40L has been reported to induce cell cycle arrest and apoptosis11–14, through a mechanism involves constitutive activation of the pro-apoptotic JNK pathway and downregulation of PI3K11,12, a known anti-apoptotic effector and regulator of gene expression23.