Clonal heterogeneity and genomic evolution in intrachromosomal amplification of chromosome 21: A case report.

This article discusses the genetic characteristics and evolution of intrachromosomal amplification of chromosome 21 (iAMP21) in childhood B‐cell acute lymphoblastic leukemia (ALL). iAMP21 is associated with poor prognosis and high relapse rates, but intensive treatment has improved outcomes. The article highlights the complexity and variability of iAMP21, including common amplified regions and secondary genetic abnormalities. The case report presented in the article describes a unique scenario where the copy number state of iAMP21 decreases at relapse, suggesting the emergence of subclones with evolving genomic alterations. The study emphasizes the importance of comprehensive genomic analyses to understand the clonal evolution of leukemia and develop tailored treatment strategies. [Extracted from the article]