Stephan received his undergraduate degrees at the University of Rostock in Biology. For his Ph.D. he moved to Hannover, where he joined the leukemia-research team for the first time working on micro RNAs in leukemia on the side of Jan-Henning Klusmann. After a successful Ph.D. he stayed in Hannover to continue his research on leukemia researching long-non coding RNAs by compiling a human blood cell atlas of non-coding RNA expression with functional implications on differentiation and leukemia-initiating-cell maintenance.

For a second post-doc he joined a research team in Rochester, expanding his knowledge of hematopoiesis further by moving on to working with naked-mole rats. Where he hypothesized the inherent potential of a mouse-sized rodent approaching 40 years of lifespan to find novel mechanisms to prevent leukemias and sustain a youthful stem cell pool.

For his third post-doc Stephan joined a Lab at the University of Lausanne, where he focused on the development of treatments to improve stem cell function in aged hematopoietic stem cells.