Accelerated aging among childhood, adolescent, and young adult cancer survivors is evidenced by increased expression of p16INK4a and frailty.

Abstract

BackgroundCellular senescence, measured by expression of the cell cycle kinase inhibitor p16INK4a, may contribute to accelerated aging in survivors of childhood, adolescent, and young adult cancer. The authors measured peripheral blood T‐lymphocyte p16INK4a expression among pediatric and young adult cancer survivors, hypothesizing that p16INK4a expression is higher after chemotherapy and among frail survivors.MethodsA cross‐sectional cohort of young adult survivors and age‐matched, cancer‐free controls were assessed for p16INK4a expression and frailty. Newly diagnosed pediatric patients underwent prospective measurements of p16INK4a expression before and after cancer therapy. Frailty was measured with a modified Fried frailty phenotype evaluating sarcopenia, weakness, slowness, energy expenditure, and exhaustion.ResultsThe cross‐sectional cohort enrolled 60 survivors and 29 age‐matched controls with a median age of 21 years (range, 17‐29 years). The prospective cohort enrolled 9 newly diagnosed patients (age range, 1‐18 years). Expression of p16INK4a was higher among survivors compared with controls (9.6 vs 8.9 log2 p16 units; 2‐sided P = .005, representing a 25‐year age acceleration in survivors) and increased among newly diagnosed patients from matched pretreatment to posttreatment samples (7.3‐8.9 log2 p16 units; 2‐sided P = .002). Nine survivors (16%) were frail and had higher p16INK4a expression compared with robust survivors (10.5 [frail] vs 9.5 [robust] log2 p16 units; 2‐sided P = .055), representing a 35‐year age acceleration among frail survivors.ConclusionsChemotherapy is associated with increased cellular senescence and molecular age in pediatric and young adult cancer survivors. Frail survivors, compared with robust survivors, exhibit higher levels of p16INK4a, suggesting that cellular senescence may be associated with early aging in survivors.