Yen held the rank of Professor and in 2023, became Emeritus at Fox Chase Cancer Center in Philadelphia, Pennsylvania.

Yen worked as a postdoctoral fellow with Don W. Cleveland at the Johns Hopkins University School of Medicine.

[1] Prior to the 1990s, the molecular mechanisms of how microtubule fibers drive chromosome movement in mitosis were largely unresolved.

As a post-doc in 1991, Tim Yen identified CENP-E, the first mitotic motor protein and found to be essential for progression through mitosis.

These include, cloning of CENP-F (a nuclear matrix protein with cell cycle specific distribution), characterization of ATM,[3] and identification of kinetochore assembly pathways.