Macrophage Inhibitory Cytokine-1: A review of its pleiotropic actions in cancer

Background and aims: The macrophage inhibitory cytokine-1 (MIC-1) is a divergent member of the transforming growth factor-beta (TGF-beta) superfamily that can serve as a potential immune-therapeutic target and/or a prognostic biomarker for the treatment of some cancers. This article reviews the current published data on the molecular and clinical application of MIC-1 in cancer. Methods: Literature review was conducted using Medline, PubMed, Embase and Cochrane databases. Results: MIC-1 is the only known secreted p53-regulated cytokine and therefore can serve as a biomarker for p53 activation both in vitro and in vivo. MIC-1 gene can be activated by cyclooxygenase inhibitors and has pro-apoptotic and anti-tumour activities. Although MIC-1 may induce anti-tumour role in the early stages of cancer, it can promote the invasiveness and metastatic behaviour in advanced stages. Greater concentration of MIC-1 was associated with the induction of cancer-related anorexia and weight loss in animals and humans. Of clinical interest, MIC-1 out-performs all available biomarkers including CA19-9 in the differentiation of patients with resectable pancreatic cancer from patients with benign pancreatic disease. MIC-1 gene was over-expressed in colorectal cancer (CRC), and a progressive rise of MIC-1 serum levels was noted in patients with adenomatous polyps and further in patients with CRC. Conclusions: MIC-1 cytokine has the potential characteristics for a new diagnostic biomarker and a target for cancer treatment. Further research however is required to characterise MIC-1 receptors and to revalidate its diagnostic power in larger and better-standardised clinical studies.