DNA modifications such as 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) are epigenetic marks known to affect global gene expression in mammals. Given their prevalence in the human genome, close correlation with gene expression and high chemical stability, these DNA epigenetic marks could serve as ideal biomarkers for cancer diagnosis. Taking advantage of a highly sensitive and selective chemical labeling technology, we report here the genome-wide profiling of 5hmC in circulating cell-free DNA (cfDNA) and in genomic DNA (gDNA) of paired tumor and adjacent tissues collected from a cohort of 260 patients recently diagnosed with colorectal, gastric, pancreatic, liver or thyroid cancer and normal tissues from 90 healthy individuals. 5hmC was mainly distributed in transcriptionally active regions coincident with open chromatin and permissive histone modifications. Robust cancer-associated 5hmC signatures were identified in cfDNA that were characteristic for specific cancer types. 5hmC-based biomarkers of circulating cfDNA were highly predictive of colorectal and gastric cancers and were superior to conventional biomarkers and comparable to 5hmC biomarkers from tissue biopsies. Thus, this new strategy could lead to the development of effective, minimally invasive methods for diagnosis and prognosis of cancer from the analyses of blood samples.

Host and tumorous inflammation actively affect liver metastasis of colorectal cancer (CRC). Neutrophils have been recognized as one active participant in metastasis procedure, with controversial roles however. Activated neutrophils release extracellular traps (NETs) which are involved in infection and multiple pathological conditions. NETs on cancer metastasis is getting recognized but less elucidated in mechanism. How NETs interact with cancer cells is still largely unknown. In this study, we found that neutrophils from CRC patients, especially those with liver metastatic, underwent remarkably enhanced NETs. Clinically, sera and pathological NETs marker closely correlated with onset of liver metastasis. Through in vivo and in vitro studies, we proved that increased NETs positively contribute to onset of CRC liver metastasis. Digesting NETs with DNase 1 diminished the increased liver metastasis associated with NETs. In detail, NETs trapped CRC cells in liver and exerted no cytotoxicity on tumor cells, but boosted tumorous proliferation and invasion capacity. We further found this enhanced malignancy of trapped CRC cells was due to the elevated tumorous interleukin (IL)-8 expression triggered by NETs. Blocking IL-8 activity effectively abrogated the enhanced proliferation and invasion triggered by NETs. Moreover, overproduced IL-8 in turn activate neutrophils towards NETs formation, thus forming a positive loop optimizing CRC liver metastasis. Collectively, our study propose a novel positive feedback between elevated tumorous IL-8 and NETs to promote CRC liver metastasis, and identify potential strategy against liver metastasis.

IMPORTANCE Gastric neuroendocrine carcinoma and mixed adenoneuroendocrine carcinoma are rare pathological types of gastric cancer, and there is a lack of multicenter studies comparing the prognosis and recurrence patterns of gastric neuroendocrine carcinoma, gastric mixed adenoneuroendocrine carcinoma, and gastric adenocarcinoma.OBJECTIVE To compare the differences in long-term survival and patterns of recurrence among gastric neuroendocrine carcinoma, gastric mixed adenoneuroendocrine carcinoma, and gastric adenocarcinoma. DESIGN, SETTING, AND PARTICIPANTSThis cohort study included patients with resectable gastric neuroendocrine carcinoma and gastric mixed adenoneuroendocrine carcinoma at 23 hospitals in China from January 2006 to December 2016. In addition, patients with gastric adenocarcinoma were selected as controls. Propensity score-matched analysis was used to match pathological stage among the different pathological types, and disease-free survival (DFS), postrecurrence survival (PRS), and patterns of recurrence were examined. Data analysis was conducted from July 15, 2020, to October 21, 2020.EXPOSURES Curative resection for gastric neuroendocrine carcinoma, gastric mixed adenoneuroendocrine carcinoma, and gastric adenocarcinoma. MAIN OUTCOMES AND MEASURESThe main outcomes were DFS and patterns of recurrence. RESULTS A total of 3689 patients were analyzed (median [interquartile range] age, 62 [55][56][57][58][59][60][61][62][63][64][65][66][67][68][69] years; 2748 [74.5%] men), including 503 patients (13.6%) with gastric neuroendocrine carcinoma, 401 patients (10.9%) with gastric mixed adenoneuroendocrine carcinoma, and 2785 patients (75.5%) with gastric adenocarcinoma. After propensity score matching, 5-year DFS was 47.6% (95% CI, 42.7%-52.5%) for patients with gastric neuroendocrine carcinoma, compared with 57.6% (95% CI, 55.1%-60.1%) with gastric adenocarcinoma (P < .001) and 51.1% (95% CI, 46.0%-56.2%) for patients with gastric mixed adenoneuroendocrine carcinoma, compared with 57.8% (95% CI, 55.1%-60.5%) patients with gastric adenocarcinoma (P = .02). Multivariable analyses found that, compared with gastric adenocarcinoma, gastric neuroendocrine carcinoma (hazard ratio [HR], 1.64; 95% CI, 1.40-1.93) and gastric mixed adenoneuroendocrine carcinoma (HR, 1.25; 95% CI, 1.05-1.49) were independent risk factors associated with worse DFS. Compared with matched patients with gastric adenocarcinoma, patients with gastric neuroendocrine carcinoma were more likely to have distant recurrence (268 patients [17.2%] vs 101 patients [23.7%]; P = .002), as were patients with gastric mixed adenoneuroendocrine carcinoma (232 patients [17.3%] vs 76 patients [22.8%]; P = .02). In (continued) Key Points Question Are there any differences in prognoses or recurrence patterns associated with gastric neuroendocrine carcinoma, mixed adenoneuroendocrine carcinoma, or adenocarcinoma? Findings This cohort study included 3689 patients with resectable gastric adenocarcinoma, gastric neuroendocrine carcinoma, or gastric mixed adeno...