DUS4L-BCAP29 is a readthrough fusion transcript generated through cis-splicing between adjacent genes on chromosome 7 1. Originally identified as a cancer-associated fusion in gastric and prostate cancers 2, subsequent research revealed that DUS4L-BCAP29 is not cancer-specific but rather a normal physiological transcript present across diverse tissues and non-neoplastic cell lines at comparable expression levels to cancer cells 13. The fusion transcript demonstrates context-dependent biological functions: in neural development, DUS4L-BCAP29 dramatically increases during neural differentiation of human umbilical mesenchymal stem cells and effectively promotes neural differentiation 4. In cellular contexts, gain-of-function studies show that DUS4L-BCAP29 overexpression promotes cell growth and motility in both cancer and non-cancer cells 13. Notably, loss-of-function approaches (siRNA knockdown) inhibited gastric cancer cell proliferation in soft agar assays, suggesting tumorigenic potential 2. However, the pro-growth effects are not uniquely oncogenic 13. DUS4L-BCAP29 cannot serve as a cancer biomarker due to its ubiquitous normal expression, but represents a functional chimeric RNA with roles in both development and cellular proliferation.