Stress granules are not present in Kras mutant cancers and do not control tumor growth

Stress granules (SG) are membraneless ribonucleoprotein-based cytoplasmic organelles that assemble in response to stress. Their formation is often associated with an almost global suppression of translation, and the aberrant assembly or disassembly of these granules has pathological implications in neurodegeneration and cancer. In cancer, and particularly in the presence of oncogenic KRAS mutations, in vivo studies concluded that SG increase the resistance of cancer cells to stress. Hence, SG have recently been considered a promising target for therapy. Here, starting from our observations that genes coding for SG proteins are stimulated during development of pancreatic ductal adenocarcinoma, we analyze the formation of SG during tumorigenesis. We resort to in vitro, in vivo and in silico approaches, using mouse models, human samples and human data. Our analyses do not support that SG are formed during tumorigenesis of KRAS-driven cancers, at least that their presence is not universal, leading us to propose that caution is required before considering SG as therapeutic targets.