Circulating tumor DNA (ctDNA) has emerged as a useful diagnostic and prognostic biomarker in many cancers. Here, we conducted a study to investigate the potential use of ctDNA methylation markers for the diagnosis and prognostication of colorectal cancer (CRC) and used a prospective cohort to validate their effectiveness in screening patients at high risk of CRC. We first identified CRC-specific methylation signatures by comparing CRC tissues to normal blood leukocytes. Then, we applied a machine learning algorithm to develop a predictive diagnostic and a prognostic model using cell-free DNA (cfDNA) samples from a cohort of 801 patients with CRC and 1021 normal controls. The obtained diagnostic prediction model discriminated patients with CRC from normal controls with high accuracy (area under curve = 0.96). The prognostic prediction model also effectively predicted the prognosis and survival of patients with CRC (P < 0.001). In addition, we generated a ctDNA-based molecular classification of CRC using an unsupervised clustering method and obtained two subgroups of patients with CRC with significantly different overall survival (P = 0.011 in validation cohort). Last, we found that a single ctDNA methylation marker, cg10673833, could yield high sensitivity (89.7%) and specificity (86.8%) for detection of CRC and precancerous lesions in a high-risk population of 1493 participants in a prospective cohort study. Together, our findings showed the value of ctDNA methylation markers in the diagnosis, surveillance, and prognosis of CRC.

A two-stage study was conducted in southern China to determine and validate an optimal combination of Epstein-Barr virus (EBV)-related seromarkers for nasopharyngeal carcinoma (NPC) screening. In the first stage, six seromarkers [VCA-IgA, EA-IgA, Epstein-Barr virus nuclear antigen 1 (EBNA1-IgA), EBNA1-IgG, Zta-IgA and Rta-IgG] were detected by enzyme-linked immunosorbent assay (ELISA) and two traditional NPC screening seromarkers (VCA-IgA and EA-IgA) were detected by immunofluorescence assay (IFA) in serum samples from 191 NPC patients and 337 controls. An optimal combination of seromarkers for NPC diagnosis was selected using logistic regression models. Results showed that the diagnostic performances of VCA-IgA and EA-IgA tested by ELISA were superior to the performances of the same seromarkers by IFA. VCA-IgA combined with EBNA1-IgA by ELISA was identified as the optimal combination, with an area under the receiver operating characteristic (ROC) curve (AUC) up to 0.97, a sensitivity of 95.3% and a specificity of 94.1% for classification of NPCs vs. controls. In the second stage, 5,481 participants aged 30-59 years and without clinical evidence of NPC were recruited into a population-based NPC screening program from May 2008 to February 2009 in Sihui City, China. Their sera were tested simultaneously by both the new and the traditional screening schemes and eight early stage NPC patients were subsequently histopathologically confirmed. The traditional and the new screening schemes had comparable specificity (estimated as 98.5%), but the sensitivity of the new scheme (75.0%) was significantly higher than that of the traditional one (25.0%). The combination of VCA-IgA and EBNA1-IgA by ELISA outperforms the traditional NPC screening scheme and could become the preferred serodiagnostic strategy for NPC screening in high-incidence areas.

ObjectiveExosomes released from tumour cells are packed with unique RNA and protein cargo, and they are emerging as an important mediator in the communication network that promotes tumour progression. The facultative intracellular bacterium Fusobacterium nucleatum (Fn) is an important colorectal cancer (CRC)-associated bacterium. To date, the function of exosomes from Fn-infected CRC cells has not been explored.DesignExosomes were isolated by sequential differential centrifugation and verified by transmission electron microscopy, NanoSight analysis and Western blotting. Given that exosomes have been shown to transport miRNAs and proteins to alter cellular functions, we performed miRNA sequencing and proteome analysis of exosomes from Fn-infected and non-infected cells. The biological role and mechanism of exosomes from Fn-infected cells in CRC tumour growth and liver metastasis were determined in vitro and in vivo.ResultsWe demonstrated that exosomes delivered miR-1246/92b-3p/27a-3p and CXCL16/RhoA/IL-8 from Fn-infected cells into non-infected cells to increase cell migration ability in vitro and promote tumour metastasis in vivo. Finally, both circulating exosomal miR-1246/92b-3p/27a-3p and CXCL16 levels were closely associated with Fn abundance and tumour stage in patients with CRC.ConclusionThis study suggests that Fn infection may stimulate tumour cells to generate miR-1246/92b-3p/27a-3p-rich and CXCL16/RhoA/IL-8 exosomes that are delivered to uninfected cells to promote prometastatic behaviours.

This study found that could play a role in microbiota dysbiosis via the secreted antagonistic substances against probiotics. Moreover, the ratio of to the important probiotics and was identified as a valuable biomarker for screening early CRC.