Aim: To explore the possibility of gastric juice (GJ)- and serum-derived SNCG as a potential biomarker for the early diagnosis of gastric cancer (GC). Materials & methods: GJ and serum samples were collected from 87 patients with GC, 38 patients with gastric precancerous lesions and 44 healthy volunteers. The levels of SNCG in GJ and serum samples were detected by ELISA. Results: The levels of SNCG in GJ and serum were significantly higher in the GC group when compared with the GPL group or the control group. The expression of SNCG in GJ and serum was associated with tumor node metastasis stage, lymph node metastasis, tumor size and drinking, and it is important for the diagnosis and prognosis of GC (p < 0.05). Conclusion: The findings highlight the significance of SNCG in GC diagnosis and prognosis and implicate SNCG as a promising candidate for GC treatment.

Breast cancer (BC) has been a serious threat to women’s health. Exosomes contain a variety of biomolecules, which is an excellent choice as disease diagnostic markers, but whether it could be applied as a noninvasive biomarker for BC diagnosis demands to be additional studied. In this study, we aimed at creating a predictive model and reveal the value of plasma exosomal miRNA (exo-miRNA) in early diagnosis of BC. Firstly, exosomes isolated from plasma were identified by Nanoparticle Tracking Analysis (NTA), Transmission Electron Microscope (TEM), and Western Blot. miRNA expression in plasma samples from 56 BC patients and 40 normal controls was analyzed by high-throughput sequencing. miRNAs with strong correlation characteristics were selected by Lasso logistic regression. Then, we built the training set and test set, evaluated the Lasso regression accuracy, and evaluated the performance of different models in the training set and test set. Finally, GO analysis, KEGG, and Reactome pathway enrichment analysis were used to understand the biological significance of 16 characteristic miRNAs. The successful separation of exosomes in serum was identified by NTA, TEM, and Western Blot. The training set data matrix containing 1962 miRNAs was obtained by sequencing for model construction, and 16 strongly correlated miRNAs were selected by Lasso logistic regression. The accuracy of Lasso regression in training set and test set were 97.22% and 95.83%, respectively. We built different models and evaluated the performance of each model in the training set and test set. The results showed that the AUC values of Lasso, SVM, GBDT, and Random Forest model in the training set were 1, and the AUC values in the test set were 0.979, 0.936, 0.971, and 0.979, respectively. Bioinformatics analysis showed that 16 signature miRNAs were significantly enriched in cancer-related pathways such as herpes simplex virus 1 infection, TGF-β signaling, and Toll-like receptor family. The results of this study suggest that the 16 characteristic miRNAs screened from plasma exosomes can be used as a group of biomarkers, and the prediction model constructed based on this set of markers is expected to be used in the early diagnosis of BC.

Kaposi's sarcoma (KS) is the second most common tumor in people infected with human immunodeficiency virus worldwide, but its pathogenesis is still unclear. In this study, we discovered that the expression of GATA‐binding protein 3 (GATA3) was lowly expressed in KS tissues and KSHV‐infected cells, while microRNA‐155 (miR‐155) was highly expressed in KS serum and KSHV‐infected cells. miR‐155 promoted the proliferation, migration and invasion of KSHV infection by targeting GATA3. Further, The KSHV‐encoded protein, the Latency associated nuclear antigen (LANA), promotes the proliferation, migration and invasion of KSHV‐infected cells by regulating the miR‐155/GATA3 axis. Regarding the molecular mechanism, c‐Jun and c‐Fos interact to form a complex. LANA upregulates the expression of c‐Jun and c‐Fos and enhances the formation of c‐Jun/c‐Fos complex. The complex binds to the −95∼−100 bp site of miR‐155 promoter and transcriptionally activates miR‐155. All in all, LANA enhances the c‐Jun/c‐Fos interaction, resulting in enhanced transcriptional regulation of miR‐155 by the c‐Jun/c‐Fos complex, thereby downregulating GATA3 and promoting the proliferation, migration and invasion of KSHV‐infected cells. The discovery of LANA/c‐Jun/c‐Fos/miR‐155/GATA3 further refines the pathogenesis of KS, potentially opening a new avenue for developing effective drugs against KS.