High IMP2 linked to poor prognosis in gallbladder cancer
Gallbladder cancer is a relatively uncommon but highly lethal malignancy, which forms in the gallbladder -- a small organ that plays a role in digestion by storing bile made by the liver. The median survival of patients with gallbladder cancer is limited to one year. The biggest challenge in the treatment of gallbladder cancer is early detection. When symptoms appear, the disease has usually reached no longer curable stage. Therefore, it's of great importance to identify new biomarkers with diagnostic potential.
Now, Dr. Sonja Kessler of Saarland University has identified a protein that is often upregulated in gallbladder cancer and correlates with poor outcome. The discovery opens up a new avenue for dealing with gallbladder cancer, although further research is still needed to elucidate the underlying mechanisms. The study, titled "IMP2/IGF2BP2 expression, but not IMP1 and IMP3, predicts poor outcome in patients and high tumor growth rate in xenograft models of gallbladder cancer," appeared last month in the journal Oncotarget.
The insulin-like growth factor 2 mRNA-binding protein 2, also known as IGF2BP2
or IMP2, is a member of the IMP family. Overexpression of IMP2 has been observed in different types of cancer, such as breast, lung, and esophageal cancer. But relatively little is known about the role of the protein in gallbladder cancer.
To address this issue, Dr. Kessler and her colleagues teamed with researchers from Medical University of Graz in Austria, Experimental Pharmacology and Oncology Berlin-Buch GmbH in Germany, Yonsei University College of Medicine in South Korea, and several other institutions.
The study enrolled hundreds of patients with gallbladder cancer. The patients' survival periods and tumor grades were investigated. Immunohistochemical staining analyses of tumor samples from the patients revealed that high expression of IMP2 and its splice variant p62 correlates with short survival and advanced tumors. To confirm the findings, the team used a murine xenograft model with different gallbladder cancer cell lines, and discovered that high IMP2/p62 expression was strongly associated with tumor growth in vivo.
Collectively, these data indicate that IMP2 has a tumor-promoting effect in gallbladder cancer. But the study has not completely illustrated how IMP2 upregulation contributes to the progression of gallbladder cancer.