MSLN and neoplasm: Significantly, immunohistochemistry for MSLN antibody showed that the expression of MSLN in tumor tissues from mice treated with αMSLN combined with OVAvac was significantly suppressed, similar to the group treated with αMSLN alone, when compared to the OVAvac or PBS‐treated groups (Combine vs OVAvac: p = 0.0006, Combine vs PBS: p = 0.0001, Figure 3M,N).