Background and Aims: Ambiguous understanding of tumors and the tumor microenvironments (TMEs) hinders accurate diagnosis and available treatment for multifocal hepatocellular carcinoma (HCC) covering intrahepatic metastasis (IM) and multicentric occurrence (MO). Here, we characterized the diverse TMEs of IM and MO identified by whole-exome sequencing (WES) at single-cell resolution. Approach and Results: We performed parallel WES and single-cell RNA sequencing (scRNA-seq) on twenty-three samples from seven patients to profile their TMEs when major results were validated by immunohistochemistry in the additional cohort. Integrative analysis of WES and scRNA-seq found that malignant cells in IM showed higher intra-tumor heterogeneity, stemness and more activated metabolism than those in MO. Tumors from IM shared similar TMEs while distinct TMEs were noticed in those from MO. Furthermore, CD20+ B cells, plasma cells and conventional type II dendritic cells (cDC2s) were decreased in IM relative to MO while T cells in IM exhibited a more terminally exhausted capacity with a higher proportion of proliferative/exhausted T cells than that in MO. Both CD20 and CD1C correlated with better prognosis in multifocal HCC. Additionally, MMP9+ tumor-associated macrophages were enriched across IM and MO which formed cellular niches with regulatory T cells (Tregs) and proliferative/exhausted T cells. Conclusions: Our findings deeply decipher the heterogeneous TMEs between IM and MO, which provide a comprehensive landscape of multifocal HCC.

中文翻译：

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多灶性肝细胞癌的基因组和肿瘤微环境异质性


背景和目的： 对肿瘤和肿瘤微环境 （TME） 的模糊理解阻碍了多灶性肝细胞癌 （HCC） 的准确诊断和可用的治疗方法，包括肝内转移 （IM） 和多中心发生 （MO）。在这里，我们表征了通过全外显子组测序 （WES） 在单细胞分辨率下鉴定的 IM 和 MO 的不同 TME。方法和结果： 当主要结果通过免疫组化在附加队列中验证时，我们对 7 名患者的 23 个样本进行了平行 WES 和单细胞 RNA 测序 （scRNA-seq），以分析他们的 TME。WES 和 scRNA-seq 的综合分析发现，IM 中的恶性细胞比 MO 中的恶性细胞表现出更高的肿瘤内异质性、干性和更活跃的代谢。此外，相对于 MO，IM 中的 CD20 + B 细胞、浆细胞和常规 II 型树突状细胞 （cDC2） 减少，而 IM 中的 T 细胞表现出更多的终末耗竭能力，增殖/耗竭 T 细胞的比例高于 MO。CD20 和 CD1C 均与多灶性 HCC 的较好预后相关。此外，MMP9 + 肿瘤相关巨噬细胞在 IM 和 MO 中富集，与调节性 T 细胞 （Tregs） 和增殖/耗竭 T 细胞形成细胞生态位。结论： 我们的研究结果深入解读了 IM 和 MO 之间的异质性 TME，这提供了多灶性 HCC 的全面景观。