Gene editing technologies help identify the genetic perturbations
driving tumour initiation, growth, metastasis and resistance to
therapeutics. This wealth of information highlights tumour complexity
and is driving cancer research towards precision medicine approaches
based on an individual’s tumour genetics. Bladder cancer is the
11th most common cancer in the UK, with high rates of relapse and
low survival rates in patients with muscle-invasive bladder cancer
(MIBC). MIBC is highly heterogeneous and encompasses multiple
molecular subtypes, each with diferent responses to therapeutics.
This evidence highlights the need to identify innovative therapeutic
targets to address the challenges posed by this heterogeneity. CRISPR–
Cas9 technologies have been used to advance our understanding of
MIBC and determine novel drug targets through the identifcation
of drug resistance mechanisms, targetable cell-cycle regulators, and
novel tumour suppressor and oncogenes. However, the use of these
technologies in the clinic remains a substantial challenge and will
require careful consideration of dosage, safety and ethics. CRISPR–
Cas9 ofers considerable potential for revolutionizing bladder cancer
therapies, but substantial research is required for validation before
these technologies can be used in the clinical setting.