Truncated FGFR2 is a clinically actionable oncogene in multiple cancers.

Somatic hotspot mutations and structural amplifications and fusions that affect fibroblast growth factor receptor 2 (encoded by FGFR2) occur in multiple types of cancer. However, clinical responses to FGFR inhibitors have remained variable, emphasizing the need to better understand which FGFR2 alterations are oncogenic and therapeutically targetable. Here we apply transposon-based screening and tumour modelling in mice, and find that the truncation of exon 18 (E18) of Fgfr2 is a potent driver mutation.

In situ CRISPR-Cas9 base editing for the development of genetically engineered mouse models of breast cancer.

Genetically engineered mouse models (GEMMs) of cancer have proven to be of great value for basic and translational research. Although CRISPR-based gene disruption offers a fast-track approach for perturbing gene function and circumvents certain limitations of standard GEMM development, it does not provide a flexible platform for recapitulating clinically relevant missense mutations in vivo. To this end, we generated knock-in mice with Cre-conditional expression of a cytidine base editor and tested their utility for precise somatic engineering of missense mutations in key cancer drivers.