Overview of the disputation
The doctoral disputation by Yizhe Sun, held on October 24, 2025, at Karolinska Institutet in Stockholm, marks a significant milestone in tumor immunology. The examination, supervised by senior and junior mentors from Karolinska Institutet and collaborating institutions, centers on the phenotypic features and functional mechanisms of tumor-associated adaptive natural killer (NK) cells. The event brings together leading researchers in tumor biology, immunology, and translational medicine to review a rigorous body of work that could influence future cancer immunotherapies.
Research focus: tumor-associated adaptive NK cells
Natural killer cells are essential actors in the innate immune response against cancer. In recent years, scientists have identified a subset of adaptive NK cells that display unique phenotypic traits and functional profiles when interacting with tumors. Yizhe Sun’s work delves into how these adaptive NK cells recognize cancer cells, how their receptors and signaling pathways differ from conventional NK cells, and how the tumor microenvironment shapes their behavior. The research addresses both the surface markers that define these cells and the intracellular pathways that govern their cytotoxicity, persistence, and potential memory-like responses.
Phenotypic features
The study examines surface receptors, transcriptional signatures, and metabolic profiles that characterize tumor-associated adaptive NK cells. By comparing adaptive NK cells to their conventional counterparts, the work highlights distinct markers that may serve as diagnostic or prognostic indicators in cancer patients. Understanding these phenotypes helps researchers predict how NK cells respond to different tumor types and stages, potentially guiding personalized immunotherapies.
Functional mechanisms
Beyond identification, the disputation investigates how adaptive NK cells exert their anti-tumor effects. Key questions include the triggers that activate these cells, the cytotoxic granule release patterns, and the cytokine milieu that supports or inhibits their activity within tumors. The research also explores how adaptive NK cells interact with other immune cells, such as dendritic cells and T cells, and how these interactions influence overall anti-tumor immunity. Findings in this area may reveal new therapeutic targets to enhance NK cell function in patients.
The disputation setting and contributors
The event is hosted at Lagerlöf, plan 4, inside the Karolinska Institutet campus, with Alfred Nobels Allé as a nearby landmark. The main supervisor is Dhifaf Sarhan, a senior lecturer and associate professor in the Division of Pathology, and mentors include professors Kaisa Lehti and Mikael Karlsson from tumor biology, virology, and immunology divisions. The opponent, Yenan Bryceson, provides critical external evaluation, ensuring rigorous appraisal of the work. The examination committee features renowned scholars Angelica Loskog, Hans Grönlund, and Hong Qian, who bring diverse expertise in immunology, neuroscience, and medicine. A dedicated content reviewer, Christina Sundqvist, helps ensure clarity and scientific rigor in the final written materials.
Why this work matters
As cancer therapies evolve, understanding the nuanced roles of NK cells in tumor settings becomes increasingly important. Adaptive NK cells could offer advantages over conventional NK cells in terms of longevity, specificity, and memory-like functions. Sun’s research not only advances basic immunology but also has potential translational implications, informing the design of NK cell–based therapies and combination strategies with other immunomodulators. The disputation thus sits at the intersection of fundamental science and clinical potential, reflecting the broader goals of the Karolinska Institutet community to translate discovery into patient benefits.
What to expect on the day
Attendees can anticipate a formal presentation by Yizhe Sun, followed by a robust question-and-answer session with the opponent and panel. The disputation will be documented for academic records, and post-event materials may summarize the core findings and future directions. For students and researchers, the event offers a valuable opportunity to engage with cutting-edge research in tumor immunology and to observe the scholarly process that advances science from hypothesis to validated knowledge.
About the organizers and participants
The disputation highlights the collaborative ecosystem at Karolinska Institutet, which brings together clinicians, scientists, and educators to push the boundaries of cancer biology and immunology. Yizhe Sun’s work stands on the shoulders of prominent researchers in tumor biology, adaptive immunity, and translational medicine, reinforced by expert oversight from the Swedish academic community. The event also emphasizes the importance of rigorous peer review in shaping impactful scientific contributions.
