It has been postulated that proteins are secreted or shed from cancer tissues [180] and it has been shown that MMRN1 is being released via exosomes by duodenal cancer cells [181] (for MMRN1 expression in duodenum adenocarcinoma cell line HuTu80, see Figure 4B), bladder cancer cells [182], and medulloblastoma cells [183]. Here, MMRN1 is linked to medulloblastoma.