Tumor-infiltrating clonal hematopoiesis was detected in 18% of patients with solid tumors and associated with older age, prior cytotoxic chemotherapy, and reduced overall survival, especially in breast cancer.
This retrospective cohort study investigated the association of TI-CH with clinical factors and its impact on OS in patients with solid tumors. The prevalence of TI-CH in this patient cohort was higher than in treatment-naive cohorts but lower than that in cohorts with higher rates of cytotoxic chemotherapy and radiotherapy. In addition, the prevalence of TI-CH was higher in patients with MSI-high colorectal tumors than in those with MSS colorectal tumors. Analysis of clinical factors revealed that each decade of increasing age and a history of cytotoxic chemotherapy were significantly associated with higher odds of TI-CH. Although TI-CH was associated with worse OS in the whole cohort (pan-cancer analysis), this outcome was most pronounced in patients with breast tumors. Furthermore, TI-CH of GATA2 in the whole cohort and TI-CH of TET2 in patients with breast tumors had the most prominent associations with worse OS.
The accumulation of somatic variants in hematopoietic stem cells with age provides a competitive advantage, leading to CHIP.2 Additionally, cytotoxic chemotherapy induces gene-specific clonal expansion by allowing clones with variants in DNA damage response genes (eg, TP53, PPM1D) to outcompete other clones because such variants are associated with chemoresistance.25 The TI-CH prevalence in our study was intermediate between treatment-naive and treatment-experienced cohorts. It was higher than in the former due to prior therapy and lower than in the latter owing to reduced exposure to cytotoxic chemotherapy and radiotherapy. This finding is notable given this study cohort’s older age, a known factor for increasing CHIP prevalence.6, 7 Furthermore, we found that TI-CH prevalence was higher in patients with MSI-high colorectal tumors than in those with MSS colorectal tumors. To our knowledge, this finding has not been previously reported.









