Background Hepatocellular carcinoma (HCC) is a prevalent malignancy with poor prognosis. As a cell adhesion molecule, poliovirus receptor (PVR/CD155) is abnormally overexpressed in tumour cells, and related to tumour proliferation and invasion. However, the potential role and mechanism of CD155 have not yet been elucidated in HCC. Methods Immunohistochemistry, RT‐PCR and Western blot assays were used to determine CD155 expression in HCC cell lines and tissues. Cell Counting Kit‐8 and colony formation assays were used to examine cell proliferation. Transwell and wound healing assays were used to evaluate cell migration and invasion. Cell apoptosis and cycle distribution were assessed by flow cytometry. Cox regression and Kaplan–Meier analyses were performed to explore the clinical significance of CD155. The role of CD155 in vivo was evaluated by establishing liver orthotropic xenograft mice model. RNA sequencing, bioinformatics analysis and co‐immunoprecipitation assay were used to explore the downstream signalling pathway of CD155. Results CD155 was upregulated in HCC tissues and represented a promising prognostic indicator for HCC patients ( n = 189) undergoing curative resection. High CD155 expression enhanced cell proliferation, migration and invasion, and contributed to cell survival in HCC. CD155 overexpression also induced epithelial–mesenchymal transition in HCC cells. CD155 function in HCC involved SRC/p38 MAPK signalling pathway. CD155 interacted with SRC homology‐2 domain of SRC and promoted SRC activation, further inhibiting the downstream p38 MAPK signalling pathway in HCC. Conclusions CD155 promotes HCC progression via the SRC/p38 MAPK signalling pathway. CD155 may represent a predictor for poor postsurgery prognosis in HCC patients.

Background Norovirus is a leading cause of acute gastroenteritis among children. Previous studies based on symptomatic infections indicated that mutations, rather than recombination drove the evolution of the norovirus ORF2. These characteristics were found in hospital-based symptomatic infections, whereas, asymptomatic infections are frequent and contribute significantly to transmission. Methods We conducted the first norovirus molecular epidemiology analysis covering both symptomatic and asymptomatic infections derived from a birth cohort study in the northern China. Results During the study, 14 symptomatic and 20 asymptomatic norovirus infections were detected in 32 infants. Out of the 14 strains that caused symptomatic infections, 12 strains were identified as GII.3[P12], and others were GII.4[P31]. Conversely, 17 asymptomatic infections were caused by GII.4[P31], two by GII.2[P16], and one by GII.4[P16]. Regardless of symptomatic and asymptomatic infections, the mutations were detected frequently in the ORF2 region, and almost all recombination were identified in the RdRp-ORF2 region. The majority of the mutations were located around the predefined epitope regions of P2 subdomain indicating a potential for immune evasion. Conclusion The role of symptomatic as well as asymptomatic infections in the evolution of norovirus needs to be evaluated continuously.

Background: Norovirus, is the leading cause of acute gastroenteritis among children. Previous studies based on symptomatic infections indicated that mutations, rather than recombination drove the evolution of the ORF2 for norovirus. However, strains causing asymptomatic infection were not considered. Methods: we conduct the first norovirus molecular epidemiology analysis covering both symptomatic and asymptomatic infections derived from a birth cohort study in the northern China. Results: During the study, 14 symptomatic and 20 asymptomatic norovirus infections were detected in 32 infants. Out of the 14 strains that caused symptomatic infections, 12 strains were identified as GII.3 [P12], and others were GII.4 [P31]; conversely, 17 asymptomatic infections were caused by GII.4 [P31], two by GII.2 [P16], and one by GII.4 [P16]. Regardless whether symptomatic and asymptomatic the mutations were detected frequently in the ORF2 region, and almost all recombinations were identified in the RdRp region. The majority of the mutations were located around the predefined epitope regions of P2 subdomain indicating a potential for immune evasion. Conclusion: The role of asymptomatic infection in the evolution of noroviruses needs to be evaluated continuously.