2026-07-30 — Aitken 2026 genetic background and experimental cancer evolution

Ingest + verification

Added and independently verified aitken-2026-genetic-background-cancer-evolution from the full article, Methods, Extended Data, reporting summary, Supplementary Note, Supplementary Tables 1–3 and Fig. 5 source data (Aitken et al., Nature, 2026; doi:10.1038/s41586-026-10821-z; PMID 42486977).
The controlled experiment exposed 215 male mice from four divergent genetic backgrounds to the same neonatal diethylnitrosamine protocol. The main analysis covered 581 histologically homogeneous dysplastic liver nodules; 16 sequenced DEN-induced HCCs were released but excluded.
Core result: inherited background altered mutation processing, selected RAS–MAPK driver, driver-by-background transcriptional response, inferred whole-genome-duplication propensity and early clonal survival. Mutation burden alone did not explain the strain-level susceptibility/latency proxy.
Evidence boundary: this is a carcinogen-induced liver-tumour study, not a normal-aging, lifespan or human-ancestry study.

Recast the paper’s “latency” as fixed, strain-specific collection endpoints based on pilot-predicted 100% macroscopic incidence, not per-animal time-to-tumour measurements.
Recorded that whole-genome duplication was inferred from mutational symmetry, variant allele frequency and nuclear size, and that the telomere-crisis explanation was associative rather than experimentally causal.
Corrected the RAS–MAPK arithmetic: 550/581 nodules carried at least one probable activating driver; the gene counts overlap because 31 nodules carried two driver genes and a different 31 carried none.
Clarified the post-MRCA result as 107/390 (27.4%) in Fig. 5 source data; the article’s 23 ± 8% is the unweighted mean ± SD across strain percentages. The Methods text reports 389 analyzable tumours, an internal discrepancy retained on the study page.

hepatocellular-carcinoma — background-dependent route from standardized damage to tumour, with the dysplastic-nodule and collection-endpoint limits explicit.
somatic-mutation-accumulation — experimental separation of mutation burden from driver compatibility and early lineage selection.
ras-mapk — pathway-level convergence alongside background-specific driver and allele choice.
mus-musculus — direct demonstration that one mouse background cannot stand for “the mouse” in this cancer model; CAROLI/EiJ identified as the separate species Mus caroli.

No general somatic-mutation theory, telomere-causality, geroprotection or human-ancestry claim was propagated.