We completed targeted exome sequencing of
the tumors of 50 patients with pTis–pT4b bladder
cancer. Mutations were categorized by type, stratified against previously identified
cancer loci in
the Catalogue of Somatic Mutations in Cancer and The Cancer
Genome Atlas databases, and evaluated in pathway analysis and comutation plots. We analyzed mutation associations with receipt of neoadjuvant chemo
therapy, nodal involvement, metastatic disease development, and survival. Compared with The Cancer Genome Atlas, we found higher mutation rates in genes encoding products involved in epigenetic regulation and cell cycle regulation. Of
the pathways examined,
PI3K/mTOR and
Cell Cycle/DNA Repair exhibited
the greatest frequencies of mutation.
RB1 and
TP53, as well as
NF1 and
PIK3CA were frequently comutated. We identified no association between mutations in specific genes and key clinical outcomes of interest when corrected for multiple testing. Discovery phase analysis of
the somatic mutations in 50 high-risk bladder
cancer patients revealed novel mutations and mutational patterns, which may be useful for developing targeted
therapy regimens or new biomarkers for patients at very high risk of disease metastasis and death.
Patient summary
In this report we found known, as well as previously unreported, genetic mutations in the tumors of patients with high-risk bladder cancer. These mutations, if validated, may serve as actionable targets for new trials.