Overexpression of PrPc, combined with MGr1-Ag/37LRP, is predictive of poor prognosis in gastric cancer

Prion protein (PrPc) has been previously reported to be involved in gastric cancer (GC) development and progression. However, the association between expression of PrPc and GC prognosis is yet poorly characterized. In the present study, the expressions of PrPc and MGr1-Ag/37LRP, a protein interacting with PrPc, were detected using the tissue microarray technique and immunohistochemical method to compare clinicopathological parameters of 238 GC patients. We found that the expressions of PrPc and MGr1-Ag/37LRP were upregulated in GC lesions compared with their expressions in adjacent noncancerous tissues (p < 0.01). High expression of PrPc was detected in 37.39% (89/238) of GC patients and positively correlated with the expression of MGr1-Ag/37LRP (r = 0.532, p < 0.001). PrPc expression was associated with a number of clinicopathological parameters including depth of invasion and lymph node metastasis of the tumor (p < 0.001). High expression of PrPc brought a poorer prognosis than low PrPc expression. Moreover, GC patients with high level of PrPc and high level of MGr1-Ag/37LRP had the poorest prognosis. Multivariate survival analysis suggested that, along with other parameters, combined expression of PrPc and MGr1-Ag/37LRP was independent prognostic factors for GC patients. These data indicates that overexpression of PrPc, combined with MGr1-Ag/37LRP, is predictive of poor prognosis in GC and thereby could be used to guide the clinical decision. WHAT'S NEW? Prion protein was originally exclusively associated with prion disease but has now been linked to other processes such as cancer and inflammation. Here the authors examined the role of prion protein and its receptor MGr1-Ag/37LRP in gastric cancer. They found that both factors were upregulated in gastric cancer, and not in neighboring healthy, tissues and established the combined expression of prion protein and MGr1-Ag/37LRP as an independent prognostic factor for gastric cancer patients. These studies support a new role of prion protein in cancer and identify a new biomarker for a more accurate prediction of prognosis in gastric cancer patients.