Speaker: Dr. Roberto Piñeiro, leads the Tumor dissemination and Circulating Tumor Cells (CTC)  Laboratory, Translational Medical Oncology Group, at the Health Research Institute of Santiago de Compostela (IDIS).

Abstract: Metastatic dissemination remains the major cause of mortality in breast cancer, yet the cellular and molecular mechanisms underlying tumor cell survival and dissemination through the bloodstream remain incompletely understood. Liquid biopsy provides a unique opportunity to study these processes directly in patients and to characterize tumor cell populations relevant to metastatic progression. Our research focuses on circulating tumor cells (CTCs), particularly CTC-clusters, as both clinically relevant biomarkers and potential mediators of metastasis.
We have investigated the clinical relevance of CTC and CTC-cluster enumeration in breast cancer, demonstrating their association with disease progression and patient outcome. Building on these observations, we have explored the biological properties of CTC clusters and their interactions with the tumor microenvironment, including their functional communication with cancer-associated fibroblasts using experimental models of tumor dissemination, such as zebrafish. These studies support the concept that CTC clusters are not simply aggregates of circulating tumor cells but represent a distinct population with specific biological properties that may facilitate metastatic spread.
More recently, we have applied single-cell genomic approaches to investigate the molecular heterogeneity of CTCs and CTC clusters and identify features associated with aggressive phenotypes. Ongoing work is further exploring candidate regulators of CTC biology and tumor-microenvironment interactions, with the aim of understanding molecular programs underlying metastatic dissemination. Together, these studies integrate clinical liquid biopsy, functional modelling and single-cell molecular profiling to advance our understanding of CTC biology and identify molecular features with potential relevance for liquid biopsy-based biomarkers and therapeutic strategies in metastatic breast cancer.

Host: Dr. Stefan Hümmer, main researcher. Translational Molecular Pathology (VHIR)