City of Hope Study Links Obesity to Cancer Risk via Organ Enlargement — City of Hope

Event summary

City of Hope and TGen published a study in Cancer Research on March 24, 2026, revealing that obesity increases cancer risk by enlarging organs, leading to more cells and higher mutation rates.
The study analyzed 747 adults across the BMI spectrum, finding that for every 5-point increase in BMI, the liver grew by 12%, kidneys by 9%, and the pancreas by 7%.
Over 60% of organ growth was due to an increase in cell number (hyperplasia), not just cell size (hypertrophy).
The findings suggest that organ dimensions may predict cancer risk better than BMI.
Future research will explore whether weight loss can reduce organ size and cancer risk, and the potential effect of GLP-1 drugs on lowering cancer risk.

The big picture

The study provides a novel mechanistic link between obesity and cancer, challenging previous assumptions about the role of cell size versus cell number in organ enlargement. This research could reshape cancer prevention strategies, particularly as obesity rates continue to rise globally. City of Hope's findings may also accelerate the development of targeted therapies for obesity-related cancers, positioning the institution as a leader in translational research.

What we're watching

Clinical Validation: Whether the study's findings can be replicated in clinical settings and translated into actionable cancer prevention strategies.
Therapeutic Implications: The pace at which GLP-1 drugs and other weight-loss interventions are developed to potentially reduce organ size and cancer risk.
Public Health Impact: How the emphasis on maintaining a healthy weight from childhood will influence public health policies and early intervention programs.