Immunosenescence profile and expression of the aging biomarker (p16(INK4a)) in testicular cancer survivors treated with chemotherapy

BACKGROUND: Cytotoxic chemotherapy can cure advanced germ cell tumors. Nevertheless, cancer treatment may induce cellular senescence and accelerate molecular aging. The aging process implies an increase of cells expressing p16(INK4a) and changes in lymphocyte subpopulations. Our aim was to study the potential induction of premature immunosenescence in testicular cancer survivors (TCS) exposed to chemotherapy. METHODS: Case-control exploratory study of TCS treated with chemotherapy (≥3 BEP cycles, disease-free ≥3 months) compared with age matched healthy controls. Peripheral blood mononuclear cells were isolated, and lymphocyte subpopulations were analyzed by flow cytometry. CDKN2A/p16(INK4a) expression in T cells was measured using qPCR. The percentage of lymphocyte subpopulations and the CDKN2A/p16(INK4a) expression in TCS were compared with the control group using the Wilcoxon signed-rank test. RESULTS: We included 16 cases and 16 controls. The median age was 27 years (minimum 24, maximum 54) and the median time on surveillance was 26.5 months (minimum 3, maximum192). TCS had a lower percentage of total T cells and CD4+ T cells in total lymphocytes. Among the CD4+ T lymphocytes, TCS had less naïve CD4+ and increased memory CD4+ cells. Within the CD8+ T lymphocytes, TCS exhibited a decrease in the percentage of naïve cells and an increase in CD8 + CD45RA + CD57+ cells. TCS also exhibited decreased memory CD19+ B cells compared to the controls. The relative expression of CDKN2A/p16(INK4a) in T cells was increased in TCS (mean 1.54; 95% CI of the mean: 1.074–2.005; p = 0.048). CONCLUSION: In this exploratory study, TCS showed increased expression of CDKN2A/p16(INK4a) and a lymphocyte phenotype that has been associated with immunosenescence. Further studies are warranted to define the clinical implications of these alterations in TCS.