[Analysis of normal tissues adjacent to the tumour-specific expressed genes in breast cancer].

Normal tissues adjacent to the tumour (NAT) are widely used as controls in comparative studies to search for cancer-associated genes. However, the gene expression profiles between NAT and non-tumour-bearing tissues are different. The presence of NAT-specific expressed genes often hinders traditional transcriptional profiles studies. Further, studies on the differences in gene expression profiles between NAT and tumour-free tissues are infrequently performed. In this study, we sequenced and analysed the transcriptomes of tumour tissues (T), matched NAT and contralateral breast normal tissues (CBN) of 14 breast cancer patients, and identified 102 differentially expressed genes (DEGs) between CBN and NAT. Gene enrichment and protein-protein interaction (PPI) analyses revealed that these DEGs are significantly enriched in TNF (tumour necrosis factor) signalling and EMT (epithelial-mesenchymal transition) gene sets closely associated with oncogenesis. Comparative analyses of the transcriptomic profiles between NAT and CBN, NAT and T identified 23 NAT-specific highly-expressed genes, namely tumour-adjacent speci?cally activated (TASA) genes. These genes were significantly enriched in TNF signalling gene set, and 15 of which have not been previously reported. The results indicate that TASA genes are common in adjacent tissues and are related to the TNF signalling in the immune system. The tumour-adjacent tissues harbour tumour-like expressed genes that could contribute to tumour initiation but are often missed in NAT-T pair-wise studies.

Dissecting spatial heterogeneity and the immune-evasion mechanism of CTCs by single-cell RNA-seq in hepatocellular carcinoma.

Little is known about the transcriptomic plasticity and adaptive mechanisms of circulating tumor cells (CTCs) during hematogeneous dissemination. Here we interrogate the transcriptome of 113 single CTCs from 4 different vascular sites, including hepatic vein (HV), peripheral artery (PA), peripheral vein (PV) and portal vein (PoV) using single-cell full-length RNA sequencing in hepatocellular carcinoma (HCC) patients. We reveal that the transcriptional dynamics of CTCs were associated with stress response, cell cycle and immune-evasion signaling during hematogeneous transportation. Besides, we identify chemokine CCL5 as an important mediator for CTC immune evasion. Mechanistically, overexpression of CCL5 in CTCs is transcriptionally regulated by p38-MAX signaling, which recruites regulatory T cells (Tregs) to facilitate immune escape and metastatic seeding of CTCs. Collectively, our results reveal a previously unappreciated spatial heterogeneity and an immune-escape mechanism of CTC, which may aid in designing new anti-metastasis therapeutic strategies in HCC.