Mutant TP53 switches therapeutic vulnerability during gastric cancer progression within interleukin-6 family cytokines

Although aberrant activation of the KRAS and PI3K pathway alongside TP53 mutations account for frequent aberrations in human gastric cancers, neither the sequence nor the individual contributions of these mutations have been clarified. Here, we establish an allelic series of mice to afford conditional expression in the glandular epithelium of KrasG12D;Pik3caH1047R or Trp53R172H and/or ablation of Pten or Trp53. We find that KrasG12D;Pik3caH1047R is sufficient to induce adenomas and that lesions progress to carcinoma when also harboring Pten deletions. An additional challenge with either Trp53 loss- or gain-of-function alleles further accelerated tumor progression and triggered metastatic disease. While tumor-intrinsic STAT3 signaling in response to gp130 family cytokines remained as a gatekeeper for all stages of tumor development, metastatic progression required a mutant Trp53-induced interleukin (IL)-11 to IL-6 dependency switch. Consistent with the poorer survival of patients with high IL-6 expression, we identify IL-6/STAT3 signaling as a therapeutic vulnerability for TP53-mutant gastric cancer. [Display omitted] •Mutant TP53 licenses progression to invasive stomach carcinoma with synchronous metastasis•Gain- and loss-of-function TP53 mutants advance gastric cancer upon loss of heterozygosity•Gastric cancer’s STAT3 addiction switches from IL-11 to IL-6 dependency when being TP53 mutant Huber et al. demonstrate that gain-of-function and loss-of-expression TP53 mutations drive gastric disease progression to aggressive carcinomas with synchronous metastasis. While STAT3 signaling remains rate limiting throughout gastric cancer progression, its cytokine dependency switches from IL-11 to IL-6 in response to the TP53 mutations observed during the transition to carcinomas.