Clinical significance of soluble form of poliovirus receptor in newly diagnosed follicular lymphoma

Background Follicular lymphoma (FL) remains an incurable malignancy with heterogeneous clinical outcomes that necessitate a better understanding of disease biology. Poliovirus receptor (PVR/CD155) is markedly overexpressed in several human malignant tumors and it has a unique dual oncoimmunoregulatory role. However, the role of the soluble form of PVR (sCD155) in FL has not been fully elucidated. Methods Soluble PVR(sCD155) were measured in the sera of 50 patients newly diagnosed with FL by sandwich enzyme-linked immunosorbent assay and compared with those of 20 healthy control participants. Moreover, we evaluated its association with the clinicopathological parameters as well as response to chemotherapy in such patients. Results Pretreatment level of sCD155 was significantly higher in patients with FL than in control participants (P<0.001). Higher levels of sCD155 were associated with aggressive high-risk clinicopathological parameters, sCD155 levels were significantly higher in FL patients with B symptoms, advanced Ann Arbor stage III and IV, bulky disease, and high-risk cytogenetic (P-value=0.01, 0.048, 0.028 and <0.001, respectively). In addition, of the 50 patients, 24 (48%) achieved CR after 4–6 courses of chemotherapy (R-CHOP), while 26 (52%) were not in remission, and higher levels of sCD155 were associated with poor response to chemotherapy (P-value<0.001). Receiver operating characteristic curve was applied. Serum level of sCD155 higher than 4.8 ng/ml is a good predictor for poor response to chemotherapy (area under the curve: 0.857, sensitivity and specificity 88.46% and 75%, respectively). Conclusion PVR (CD155) is a potential therapeutic target that warrants further investigations and serum sCD155 may be used as a biomarker of treatment response and for predicting poor outcome in FL.