Roles of Polyploid/Multinucleated Giant Cancer Cells in Metastasis and Disease Relapse Following Anticancer Treatment

Tumors and tumor-derived cell lines contain polyploid giant cells with significantly elevated genomic content, often with multiple nuclei. The frequency of giant cells can increase markedly following anticancer treatment. Although giant cells enter a dormant phase and therefore do not form macroscopic colonies (aggregates of >= 50 cells) in the conventional in vitro colony formation assay, they remain viable and metabolically active. The purpose of this commentary is to underscore the potential importance of polyploid/multinucleated giant cells in metastasis and cancer recurrence following exposure to anticancer agents. We also discuss the possibility that most preclinical (cell-based and animal model) drug discovery approaches might not account for delayed responses that are associated with dormant giant cells.