Mixed responses to targeted therapy driven by chromosomal instability through p53 dysfunction and genome doubling

Area of Science:

• Oncology
• Genetics
• Molecular Biology

Background:

• Mixed or heterogeneous treatment responses in cancer patients pose clinical challenges.
• The molecular underpinnings of intra-patient tumor heterogeneity remain largely unknown.

Purpose of the Study:

• To investigate the molecular basis of mixed intra-patient tumor responses to EGFR tyrosine kinase inhibition (TKI) in metastatic lung adenocarcinoma.
• To explore the role of co-mutations and genomic alterations in treatment resistance.

Main Methods:

• Comparative analysis of lung adenocarcinoma patients with EGFR mutations alone versus EGFR and TP53 co-mutations.
• Utilizing mouse models and in vitro isogenic p53-mutant cell systems.
• Assessing the impact of whole genome doubling (WGD) on genomic instability and gene copy-number alterations.

Main Results:

• Patients with co-occurring EGFR and TP53 mutations exhibit a higher likelihood of mixed intra-patient responses to EGFR TKI compared to those with EGFR mutations alone.
• The combination of WGD and TP53 co-mutations significantly increases genome instability and copy-number aberrations in genes associated with EGFR TKI resistance.
• WGD facilitates diverse resistance mechanisms by elevating the probability of acquiring copy-number gains or losses.

Conclusions:

• Provides a molecular explanation for heterogeneous tumor responses within individual patients undergoing targeted therapy.
• Highlights the critical role of WGD and TP53 co-mutations in driving EGFR TKI resistance in lung adenocarcinoma.
• Suggests implications for refining therapeutic strategies in patients with complex genomic profiles.