Highlights d We build the genomic and transcriptomic landscape of 133 cHCC-ICCs d Integrative genomic analysis reveals distinct cHCC-ICC subtypes d Both mono-and multiclonal origins of cHCC-ICC are identified d Nestin expression can serve as a biomarker for the diagnosis and prognosis of cHCC-ICC

The extent of intratumor heterogeneity varies considerably among patients with HCC. Therefore, sequence analysis of a single lesion cannot completely characterize the genomic features of HCC in some patients. Genomic comparisons of multiple lesions associated with HCCs will provide important information on the genetic changes associated with tumor progression.

Polyploidy is associated with increased cell size and is commonly found in a subset of adult organs and blastomere stage of the human embryo. The polyploidy is formed through endoreplication or cell fusion to support the specific need of development including earliest embryogenesis. Recent data demonstrated that Polyploid Giant Cancer Cells (PGCCs) may have acquired an activated early embryonic-like program in response to oncogenic and therapeutic stress to generate reprogrammed cancer cells for drug resistance and metastasis. Targeting PGCCs may open up new opportunities for cancer therapy.

Liver cancer is the second most common cause of cancer-related death worldwide. Approximately 70–90% of primary liver cancers are hepatocellular carcinoma (HCC). Currently, HCC patient prognosis is unsatisfactory due to high metastasis and/or post-surgical recurrence rates. Therefore, new therapeutic methods for inhibiting metastasis and recurrence are urgently needed. Exosomes are small lipid-bilayer vesicles that are implicated in tumour development and metastasis. Rab27a, a small GTPase, regulates exosome secretion by mediating multivesicular endosome docking at the plasma membrane. However, whether Rab27a participates in HCC cell-derived exosome exocytosis is unclear. Epithelial-mesenchymal transition (EMT) frequently initiates metastasis. The role of HCC cell-derived exosomes in EMT remains unknown. We found that exosomes from highly metastatic MHCC97H cells could communicate with low metastatic HCC cells, increasing their migration, chemotaxis and invasion. Rab27a knockdown inhibited MHCC97H-derived exosome secretion, which consequently promoted migration, chemotaxis and invasion in parental MHCC97H cells. Mechanistic studies showed that the biological alterations in HCC cells treated with MHCC97H-derived exosomes or MHCC97H cells with reduced self-derived exosome secretion were caused by inducing EMT via MAPK/ERK signalling. Animal experiments indicated that exosome secretion blockade was associated with enhanced lung and intrahepatic metastasis of parental MHCC97H cells, while ectopic overexpression of Rab27a in MHCC97H cells could rescue this enhancement of metastasis in vivo. Injection of MHCC97H cell-derived exosomes through the tail vein promoted intrahepatic recurrence of HLE tumours in vivo. Clinically, Rab27a was positively associated with serum alpha-fetoprotein (AFP) level, vascular invasion and liver cirrhosis. Our study elucidated the role of exosomes in HCC metastasis and recurrence, suggesting that they are promising therapeutic and prognostic targets for HCC patients.

Tumor angiogenesis plays a critical role in the tumor progression. Highly upregulated in liver cancer (HULC) is a long noncoding RNA (lncRNA) that acts as an oncogene in gliomas. We found that HULC, vascular endothelial growth factor (VEGF), and ESM-1 (endothelial cell specific molecule 1) expression and microvessel density were positively correlated with grade dependency in glioma patient tissues, and that HULC silencing suppressed angiogenesis by inhibiting glioma cells proliferation and invasion. This process induced anoikis and blocked the cell cycle at G1/S phase via the PI3K/Akt/mTOR signaling pathway, thus regulating the tumor-related genes involved in the above biological behavior in human glioma U87MG and U251 cells. However, these effects were reversed by ESM-1 overexpression, suggesting a mediating role of ESM-1 in the pro-angiogenesis effect of HULC. Our results define the mechanism of the pro-angiogenesis activity of HULC, which shows potential for application as a therapeutic target in glioma.