What kind of lives have the world’s leading researchers lived—and what thoughts have driven them to explore the unknown?
In this interview series, Inventor’s Vision, we delve into the personal journeys and philosophies of scientists who are pushing the frontiers of knowledge.
This time, we feature Professor Ayuko Hoshino of the Research Center for Advanced Science and Technology (RCAST), The University of Tokyo.
Dr. Hoshino is a pioneering researcher in exosome science, working to uncover the mechanisms behind complex diseases. Her research journey began during her university years, when a close friend was diagnosed with osteosarcoma—a life-changing experience that deeply influenced her path.
In this interview, we explore her philosophy of bringing basic science into society, as well as the powerful personal story that underpins her work.
▶︎ Read the previous article here
“Focus on what you can control.”
How a Life Philosophy Was Formed During Childhood in America
— Dr. Hoshino, who is working to uncover the potential role of exosomes in various diseases, what kinds of things interested you when you were a child?
I loved music. Especially during elementary school, I was very passionate about playing the clarinet.
Actually, due to my father’s work, I spent about six years living in the United States — in New York State and Georgia — starting at the end of my first-grade year.
I couldn’t speak any English at the time, but rather than attending a Japanese school abroad, I enrolled in local American schools.
Because of that, playing the clarinet, which only required reading music rather than speaking a language, became one way for me to integrate into the school community.
After being captivated by the sound of the clarinet during a school music class, I begged my parents to buy me one. Throughout my elementary school years, I performed in the school orchestra and brass band.
I still vividly remember how much I enjoyed hearing the melodies I played blend dynamically with the sounds of other instruments.
— Are you still playing the clarinet today?
I continued through high school, but after that, I got involved in activities like basketball, and unfortunately, I didn’t have many opportunities to keep playing music.
Still, I hope to pick it up again someday.
One of my quiet dreams for the future is to join the local community orchestra after I retire.
— Elementary school years are often a formative time when foundational ways of thinking and personality are developed. How did spending those years in the U.S. influence your life, Dr. Hoshino?
I believe it had a significant impact on me.
I have many fond memories from my time living there, but I also experienced my fair share of challenges, cultural differences, and moments of confusion.
Today, Japanese food is widely recognized and celebrated overseas, but back then it was still quite rare. When I brought rice balls (onigiri) to school for lunch, my classmates were surprised. Even though I couldn’t fully understand what they were saying, I could tell from their reactions—like when they saw the seaweed wrapped around my onigiri and exclaimed, “Ew, Ayuko’s eating something black!”—that they were put off by it.Even though my mother had lovingly made those rice balls, as a child, I didn’t want to keep experiencing those reactions, so I eventually stopped bringing onigiri to school.
When I first arrived in the U.S., simply keeping up with classes was a struggle.
For example, in a class similar to Japanese “kokugo” (language arts), we often played games where teams competed to see who could look up words in the dictionary the fastest. For me, these activities weren’t particularly enjoyable. Because I was still unfamiliar with English, I was very slow at looking up words, and my teammates would often react with visible disappointment, saying things like, “We’re last again,” or “Looks like we’re the last to go for recess.””
Through these experiences, I realized something important:
“Don’t worry too much about things that are beyond your control.”
You can’t control other people’s thoughts or feelings.
As long as I did my best in what I could control, there was no point in obsessing over how others might see me. That mindset has remained with me ever since.
— Today, with the widespread use of social media, it’s easy to become overly sensitive to other people’s opinions. The idea of “focusing on what you can control” is gaining more attention. It sounds like you already had that mindset from your elementary school days.
At that time, I couldn’t articulate it as clearly as I can now.It wasn’t until high school that I was able to put my way of thinking into words.
Back then, I encountered a line from Hamlet that left a strong impression on me:
“There is nothing either good or bad, but thinking makes it so.”
When I read those words, I felt an immediate sense of agreement — it captured exactly what I had been feeling. That experience helped me finally express my own stance in words.
Inspired to Pursue Cancer Research by a Friend’s Battle with Illness
— When did you first become interested in the sciences?
It was during my first year of high school.
I studied abroad in Michigan, in the United States, and in a chemistry class, I learned about the periodic table.
Discovering that everything in the world is made up of the elements listed in that table left me deeply moved—it was a major turning point for me.
— And that’s what led you to study applied chemistry at the Faculty of Science at Tokyo University of Science?
That’s right.
At university, I became particularly interested in organic chemistry and analytical chemistry and continued to deepen my studies in those fields.
— In a previous interview, you mentioned that you studied cancer during graduate school. What led you to choose cancer as your research theme?
There’s a scene from my university days that I will never forget—it’s the experience that inspired me to pursue cancer research.
At the time, a friend from my basketball club was diagnosed with osteosarcoma, a type of bone cancer. My friend was hospitalized in a major hospital to undergo treatment, and I decided to visit without thinking too much about it.
Since it happened to be around lunchtime, I stopped by a fast-food chain, bought a hamburger and fries, and brought them with me to the hospital. I sat in a large shared hospital room, where several children, including my friend, were being treated, and started eating while chatting with my friend.
Before long, however, I noticed that something was wrong.
As you might imagine, hamburgers and fries have a very strong smell. And the children in the hospital, due to their treatment, hadn’t been able to eat fast food for a long time. I heard one of the children, drawn by the smell of the food, pleading with their parent in a small, earnest voice: “I want to eat fries, too.”
That moment hit me like a shock.
I realized that, in front of children fighting serious illnesses—children who couldn’t eat what they wanted when they wanted—I had thoughtlessly brought and eaten fast food. Even though I was young, I felt deeply ashamed and heartbroken over how inconsiderate and cruel my actions had been. At the same time, I clearly saw the reality of children fighting diseases like osteosarcoma, clinging to hope alongside their parents.
Through that experience, I truly came to understand the weight of words like “childhood cancer” and “incurable disease.”
It made me think about how I might use my background in chemistry to contribute to cancer research. After all, human beings are made up entirely of elements from the periodic table—mostly oxygen, carbon, hydrogen, and nitrogen, some of the simplest elements. Precisely because life is built from such simple components, it can become extraordinarily complex. But I thought, if we harness the power of science, maybe we can one day overcome cancer.
That was the beginning of my journey to make cancer the focus of my research.
Building the Foundation as a Researcher at Cornell University
— After completing your undergraduate studies, you pursued graduate work at the Department of Advanced Life Sciences, Graduate School of Frontier Sciences, The University of Tokyo.
Yes.
I decided to enter the University of Tokyo’s graduate school because there was a professor affiliated with the National Cancer Center conducting cancer research there. The laboratory had many physicians engaged in clinical research, so it was truly an ideal environment for me to gain a deeper understanding of cancer treatment and the reality of battling the disease.
— After graduate school, what led you to move to the Department of Pediatrics at Weill Cornell Medical College?
Just before I entered the second year of my master’s program, I attended a research presentation that would end up shaping my career.
Although I had entered graduate school with the determination to “eliminate cancer,” the more I learned about the diversity of cancers and the complexity of developing treatments, the more I began to feel that truly eradicating cancer might be impossible.
It was during this time that I heard that Dr. David Lyden from Cornell University—who was studying the mechanisms of cancer metastasis—would be visiting Japan to give a presentation. I volunteered to help at the conference where he was speaking.
There, I encountered the concept of the “pre-metastatic niche” and the idea that cancer might predetermine future sites of metastasis—ideas that resonated deeply with me and continue to shape my research today.
I was struck by how well this matched my personal experiences: my friend who had osteosarcoma, as well as several children who had shared the same hospital ward, had all developed lung metastases, which ultimately worsened their conditions. I intuitively felt that the notion that “different types of cancer have preferred metastatic destinations” was absolutely true.
If the future sites of metastasis are already determined, then perhaps we could intervene and prevent metastasis from happening in the first place, thereby reducing cancer-related deaths.
Seeing a new hope for the future of cancer research, I immediately approached Dr. Lyden after his talk and expressed my desire to study under him at Cornell. At the time, I hadn’t yet entered a Ph.D. program, so we simply exchanged contact information.
After that, I stayed in touch with him regularly, and when it finally became clear that I would complete my PhD, I contacted him again—and he welcomed me with open arms, saying, “I’ve been waiting for you.”
— How was your research life at Cornell University?
It was stimulating and incredibly enjoyable.
In a good way, every day felt like a battle—not against others, but against the constant unknowns and challenges that research throws at you. I was always in a state of readiness.
At Cornell, it didn’t matter where you were from, what year you were in, or how much experience you had—everyone was expected to speak up in meetings. Opportunities for sudden presentations were also common.
While advancing my own research, I had to constantly accumulate new knowledge and formulate my own ideas and opinions.
Through that process, I feel I was trained to develop a wide range of essential skills as a researcher.
— Have your experiences in the U.S. influenced how you run your own laboratory today?
Absolutely.
For example, whether in Japan or the U.S., the path to success in academia is never clearly laid out—and in fact, there is no single “correct” route.
However, compared to Japan, I feel that in the U.S., it’s more common for supervisors and senior researchers to proactively point out goals or milestones that you should be aiming for at your current stage.
Having that kind of guidance helped me move forward steadily, even when I felt lost.
I, too, struggled many times, but I was often saved by the advice of my mentors, which gave me the reassurance that I was generally on the right path. Because of these experiences, I consciously try to provide feedback to students and researchers in my lab—to offer a kind of compass for them as they navigate their own journeys.
I’m also very mindful about creating an environment where people from diverse backgrounds can thrive.
At Cornell, researchers came from all kinds of different backgrounds, regardless of gender or nationality. I saw firsthand that rich diversity fosters unique and powerful research. Based on that realization, I want my lab to be a place where people of different research histories, universities, ages, genders, and nationalities can stimulate and inspire each other.
At a recent SS-F event, I talked about how “being challenged by perspectives from outside your usual framework leads to growth and new insights.”
I hope to continue building a lab that serves as exactly that kind of space—where discoveries are sparked by fresh, diverse viewpoints.
— Finally, Dr. Hoshino, how would you describe what it means to be a researcher?
Lately, I’ve come to think that researchers are “people who build bridges.” This idea was inspired by something my six-year-old daughter said.
One day, she told me, “Researchers are people who invent things, right?” Of course, there is an aspect of research that involves inventing technologies that contribute to society. But the role of a researcher doesn’t end there.
Researchers also discover new knowledge and play a crucial role in educating the next generation. Depending on which aspect they emphasize, a researcher may appear as an inventor, an educator, or an intellectual explorer. These roles are not independent or in conflict—they overlap and complement one another.
For example, in the field of quantum mechanics, the original focus was purely theoretical exploration. However, over time, the theories developed by many researchers laid the foundation for advancements in semiconductor technology and information science. Discoveries in fundamental knowledge, when viewed over the long term, often lead to the development of new technologies and contribute to societal progress.
Thus, I believe the true mission of a researcher is to connect and build bridges—between knowledge and knowledge, theory and practice, education and research, the past and the future.
Standing on this belief, I feel my mission is to connect research with society.
I will continue to pursue my research, never forgetting the origin of my journey—my friend’s battle with osteosarcoma—and the feelings that motivated me at the very beginning.
I hope that one day, my research will have a real, practical impact in clinical settings.
Profile
Ayuko Hoshino
Professor, Research Center for Advanced Science and Technology (RCAST), The University of Tokyo.
Dr. Hoshino completed her Ph.D. in 2011 at the Graduate School of Frontier Sciences, The University of Tokyo. She then spent over eight years at Weill Cornell Medical College (U.S.), where she progressed through positions as a postdoctoral researcher, Research Associate, and Instructor, before becoming an Assistant Professor.
In April 2019, she returned to Japan to join the International Research Center for Neurointelligence (IRCN) at the University of Tokyo as a Lecturer.
In March 2020, she established her own lab as an Associate Professor at the School of Life Science and Technology, Tokyo Institute of Technology, and since March 2023, she has served as a Professor at the Research Center for Advanced Science and Technology (RCAST), The University of Tokyo.
(Interview & Text: Teruko Ichioka / Photos: Kayo Sekiguchi)
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