Telomere shortening upon cell divisions provides a natural barrier against indefinite cellular proliferation. If the tumorigenic process is usually associated with the acquisition of a telomere maintenance mechanism, it emerged quite recently that this is not an absolute requirement for tumor formation and/or metastasis formation. In the first part of the seminar, I will revisit the concept of cancer cell immortality in melanoma tumors1. The second part will be dedicated to the description of the telomerase-independent alternative (ALT) mechanism of telomere maintenance, of special relevance in the context of solid pediatric tumors2. I will present the tools that we developed to diagnose the ALT mechanism on tumor sections3. I will then go through the perspectives for anti-ALT therapies in cancer treatment and present one possible ALT target that we identified in the lab4,5. At the end of the seminar, I will briefly present additional ongoing research on ALT in our group.

1. Viceconte N, .., Decottignies A. 2017. Cell Rep, 19(12):2529-43
2. Claude E & Decottignies A. 2020. Curr Opin Genet Dev, 60:1-8
3. Claude E, .., Decottignies A. 2021. Mol Biomed, 2(1):32
4. Episkopou H, .., Decottignies A. 2019. Mol Cell, 75(3):469-82
5. Claude E, .., Decottignies A. 2019. Mol Cell Oncol, 6(6):e1651603