http://english.cas.cn/newsroom/research_news/life/202507/t20250718_1047649.
A study from the CAS Institute of Genetics and Developmental Biology has revealed how recently evolved human-specific genes—critical for brain development and cognitive abilities—can be hijacked by cancer to drive tumor growth.
Unlike most genes that evolve through duplication and modification of existing ones, de novo genes emerge from non-coding DNA, encoding entirely new biological functions. The researchers identified 37 such genes unique to humans and our closest ape relatives based on 120 mammalian genomes, 1,900 human transcriptomes, and 100 million protein spectra. These genes are typically active only in the brain and testes during early development. There they helped shape uniquely human features such as our enlarged brain and improved cognitive capacity over the course of evolution, according to the team’s previous studies.
But cancer hijacks these same genes. By analyzing 5,278 tumor samples spanning 22 cancer types, the researchers discovered that nearly half of these genes become aberrantly activated in cancerous tissues—often through the formation of extrachromosomal circular DNA (ecDNA). Functional assays using CRISPR-Cas9 and siRNA confirmed that 57% of these genes directly promote tumor cell proliferation, and their overexpression correlates with worse patient outcomes.
The researchers focused on two human-specific genes, ELFN1-AS1 and TYMSOS. They are completely absent in other species, inactive in healthy adult tissues, but get reactivated only in tumors. In collaboration with Peking University, the researchers developed mRNA vaccines that train the immune system to recognize these tumor-specific proteins. In humanized mouse models, the vaccines induced robust anti-tumor immune responses, especially when combined with existing immunotherapies. Patient immune cells also showed antigen‑specific immune responses, suggesting a promising new approach.
