For instance, Hassan et al. found in patients with mesothelin-expressing solid tumors that serum levels of soluble mesothelin-related peptides (SMRPs) and megakaryocytic potentiating factor (MPF) decreased with treatment and were significantly lower in patients with radiographical response [137] and similar findings have been seen in prostate cancer patients and those with brain tumors [112,114]. The gene discussed is MSLN; the disease is prostate cancer.