Genome profiles of lymphovascular breast cancer cells reveal multiple clonally differentiated outcomes with multi-regional LCM and G&T-seq

Lymphovascular invasion (LVI) is a critical step in the metastatic process but has received relatively little attention due to the technical challenges associated with their isolation. In this study, we used laser capture microdissection (LCM) to isolate 97 cancer cell clusters from pathological frozen sections within lymphatic vessels, primary tumor tissue, and axillary lymph nodes of a triple negative breast cancer (TNBC) patient. Simultaneous genome and transcriptome amplification and sequencing (G&T-seq) performed on these clusters permitted a comprehensive depiction of the genomic and transcriptional profiles of cancer cells associated with LVI. Combination phylogeny analysis pointed to three evolutionarily distinct pathways of tumor clone development and metastasis in this patient, each of which was associated with a unique mRNA signature, and correlated to disparate overall survival outcomes. Moreover, hub gene evaluation found extensive down regulation of ribosomal protein mRNA to be a potential marker of poor prognosis in breast cancer patients.