A study from MD Anderson Cancer Center analyzed 94 tumors across seven cancer types, using single-cell sequencing on over 62,000 aneuploid cells.
Key Findings
Cancer cells within tumors share early-stage copy number alterations (CNAs), indicating a common single ancestral cell. This foundational finding suggests that tumors originate from one rogue cell before branching out.
Tumors evolve through sudden bursts of genetic changes (punctuated evolution) rather than gradual accumulation. This challenges the traditional view of slow, step-by-step mutation.
Higher genetic diversity is associated with distinct spatial regions within tumors, more aggressive disease, and poorer clinical outcomes. The more varied the cells within a tumor, the worse the prognosis tends to be.
The Punctuated Evolution Index (PEI) quantifies the degree of sudden CNA bursts; high PEI correlates with rapid acquisition of genetic drivers and advanced disease. This new metric could serve as a powerful clinical biomarker.
Methodology
Researchers employed a multi-omics approach, combining single-cell sequencing, whole-exome sequencing, and RNA sequencing. Patient samples were collected from seven cancer types: bladder, breast, colon, glioblastoma, kidney, lung, and ovarian.
By measuring copy number alterations (CNAs) across thousands of individual cells, the team was able to reconstruct detailed evolutionary trees for each tumor. This reconstruction revealed the timing and sequence of genetic changes.
Implications
The findings provide a framework for understanding intratumoral diversity, which may improve diagnostics and personalized treatments. By identifying patients with high genetic diversity or a high PEI, clinicians could flag those at greater risk of aggressive disease or treatment resistance.
This research lays the groundwork for new diagnostic tools that monitor how a tumor is evolving in real time, potentially enabling earlier interventions and more tailored therapeutic strategies.