The oncogenic driving force of CD30 signaling‐induced chromosomal instability in adult T‐cell leukemia/lymphoma

Adult T‐cell leukemia/lymphoma (ATL) develops via stepwise accumulation of gene mutations and chromosome aberrations. However, the molecular mechanisms underlying this tumorigenic process are poorly understood. We previously reported the presence of a biological link between the expression of CD30, which serves as a marker for ATL progression, and the actively proliferating fraction of human T‐cell leukemia virus type 1 (HTLV‐1)‐infected cells that display polylobulation. Here, we demonstrated that CD30 signaling induced chromosomal instability with clonal expansion through DNA double‐strand breaks (DSBs) via an increase of intracellular reactive oxygen species. CD30(+)ATL cells were composed of subclones with additional genomic aberrations compared with CD30(−)ATL cells in ATL patients. Furthermore, we found an accumulation of copy number loss of DSB repair‐related genes as the disease progressed. Taken together, CD30 expression on ATL cells appears to be correlated with genomic instability, suggesting that CD30 signaling is one of the oncogenic factors of ATL progression with clonal evolution. This study provides new insight into the biological roles of CD30 signaling and could improve our understanding of tumorigenic processes of HTLV‐1‐infected cells.