AI Insight
Researchers analyzed whole-genome sequences from 97 rhabdoid tumors (aggressive pediatric cancers) and found that while the initial cancer-causing genetic mutation (bi-allelic loss of SMARCB1 or SMARCA4) occurred very early in prenatal development, the actual tumor growth often did not begin until months or years later during infancy. By tracking specific genetic changes and age-related mutations, they determined that 42% of cases involved a particular type of mutation (CN-LOH) and discovered a variable time gap between the founding genetic event and tumor expansion. This suggests that additional factors beyond the initial genetic mutation are necessary to trigger actual tumor development.
Why it matters
This finding challenges the assumption that cancer-causing mutations immediately lead to tumor growth and suggests there may be a window of opportunity for early intervention in children carrying these mutations. Understanding what triggers the delayed tumor expansion could lead to new prevention strategies or early detection methods for these deadly childhood cancers.
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⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Rhabdoid tumors are very aggressive rare pediatric cancers with poor survival affecting very young children. They are characterized by the bi-allelic loss of SMARCB1 or SMARCA4, which is suspected to occur prenatally. However, their genomic evolution is not well understood. Here we assembled the largest cohort of whole-genome sequenced rhabdoid tumors to date, comprising 97 tumors from 88 children. We discovered that, in 42% of cases, the bi-allelic inactivation of the driver gene occurred via a Copy Number Neutral-Loss of Heterozygosity (CN-LOH). We exploited these CN-LOH events and the steady accumulation of age-related mutations in the tumor genomes to estimate the age of donors at the time of occurrence of the driver event and at the time of emergence of the clonal expansion. Across all cases with CN-LOH, the loss of the driver gene occurred very early during prenatal development. However, the clonal expansion that ultimately gave rise to the tumor occurred at different times during infancy, even several years after the acquisition of the founder event. These results indicate that probably other factors, besides the genetic driver event, are required to promote rhabdoid tumorigenesis.
Source: Variable latency between the founder genetic event and rhabdoid tumor expansion