The TITANIA (mulTi omIcs daTa cANcer dIagnostics therApies) study is an international collaboration to generate high-quality multi-omics cancer profiles. We conducted an exploratory investigation within this framework to understand the molecular basis of lymphovascular invasion (LVI), a critical determinant of metastatic potential in clear cell renal cell carcinoma (ccRCC). We analyzed 31 ccRCC specimens (11 LVI+, 20 LVI-) from the National Cancer Center Hospital East using whole-genome sequencing, RNA sequencing, and proteomic profiling. Our findings were integrated with public single-cell RNA sequencing (GSE159115) and spatial transcriptomics (GSE175540) datasets to provide a broader biological context. LVI+ tumors consistently showed a distinctive hepatic-lineage gene expression signature, with significant upregulation of aldolase B (ALDOB) and other liver-specific metabolism genes at both the RNA and protein levels. Single-cell analysis identified a previously unrecognized hepatic-differentiated tumor subpopulation expressing master transcription factors HNF1A and HNF4A, which was positioned at the terminal stages of tumor evolution. Comparison with established hepatocyte gene signatures from three independent databases confirmed enrichment of hepatic metabolic programs in this subpopulation. Spatial transcriptomics revealed preferential localization within hypoxic tumor regions. A metabolic program resembling hepatic lineage differentiation, associated with aggressive disease features including LVI and hypoxic microenvironments, offers preliminary insights into renal cancer progression and potential biomarker development. This is a discovery-based, hypothesis-generating study; all findings require independent functional validation before clinical application.
Yajima et al. (Wed,) studied this question.