In the face of old school mores, self-motivation and perseverance were needed to build a career as a nationally regarded blood and bone marrow transplant expert. “I was born and reared in Brooklyn, New York, the oldest of seven children of Irish-Italian parents who did not espouse professional careers for women. In fact, my father was so old school that he didn’t think women should even attend college,” said Mary M. Horowitz, MD, MS.

Mary M. Horowitz, MD, MS

TITLE
Professor and Deputy Cancer Center Director, Medical College of Wisconsin

MEDICAL DEGREE
MD, Medical College of Wisconsin

ON THE EVOLVING FIELD OF BONE MARROW TRANSPLANTATION
“When I started, all of the patients were under 40, and the donors were HLA-matched siblings. The regimens were myeloablative, and although the outcomes were better than with conventional chemotherapy, they were still not very good. Now, two-thirds of transplants use autologous cells, which was a huge development that took place in the 1990s. And for patients who need an allogeneic donor, there is pretty much universal donor availability with ability to use HLA-mismatched related and unrelated donors and umbilical cord blood, with important innovations in preventing both graft rejection and graft-vs-host disease. Now, we do transplants in patients in their 70s, and the median age is mid-50s. Plus, a whole host of supportive care innovations have truly transformed the field.“

She continued: “When I was going to school, I was a good student, but going to medical school never occurred to me. I thought about becoming a nurse or a teacher, or, of course, a secretary, which were more traditional jobs for women at that time. That said, I liked science so much that I asked for a chemistry set for Christmas one year. So, after high school, I entered the State University College of New York in Buffalo with the intention of becoming a special education teacher. I have a brother who had severe learning disabilities, and all through high school, I’d done volunteer work with kids and adults with cognitive challenges.”

New Horizons

When Dr. Horowitz left Brooklyn and entered the university environment, her perspective on education and career opportunities opened. “One of my classmates was a graduate student in biology. I quickly found myself intrigued by what he was doing in the laboratory and peppered him with questions. Whenever we were together, that’s all I wanted to talk about. At one point, he said I shouldn’t be a teacher, I should go to medical school and become a doctor or clinical researcher. I thought about what he said, and it made sense,” said Dr. Horowitz.

Serendipity also played a hand in Dr. Horowitz’s career path as she was accepted into a newly formed independent study program. “The program’s director was a terrific man named Richard Meisler, PhD. When I told him I was thinking about changing my major from special education to perhaps pre-med, he said his wife was a molecular biologist, and he got me a job working in her laboratory for 6 months. I loved the lab and felt I’d possibly found my career path. However, ever since I was in grade school, I’d convinced myself that I was going to be a special education teacher, so I felt it was only right to give it a chance and work in a classroom for a while before making a decision,” said Dr. Horowitz.

Dr. Horowitz told her then boss who headed the lab about her childhood dream of becoming a teacher and how she felt she needed to test those waters before making a final career decision. “She told me that her brother was a teacher in Milwaukee and that I could go there and work with him. Undeterred, I spent a semester in her brother’s classroom and ultimately decided that teaching wasn’t for me,” said Dr. Horowitz. “But I did end up marrying a teacher.”

The Big Sit-Down

Although Dr. Horowitz had decided to pursue a career in medicine, she was on the fence about whether to go to graduate school or pursue her medical degree. “In the end, I decided on medical school because the thought of constantly having to publish papers and write grants turned me off from pursuing a graduate degree. Ironically, I would spend a lot of my future career doing just that,” said Dr. Horowitz.

Asked about her parents’ reaction about her decision to become a physician, Dr. Horowitz replied: “Oh, they thought it was terrible. I was already married, and my parents were sure that it would ruin my marriage. For one, my husband was an elementary school teacher, and they felt the marriage wouldn’t survive the imbalance in prestige and salary. My husband, in fact, was an extraordinary teacher who’d been written about and highly noted. He was totally supportive of my career. People used to ask if it bothered him that I would make more money than he did, but that question didn’t even register. He’d laugh it off and say, ‘Hey, it’s great because I think she’s going to let me spend it,’” said Dr. Horowitz.

To further add to Dr. Horowitz’s parents’ dismay over her decision to become a doctor, her first child was born 8 weeks before she entered medical school. “When my parents found out I was pregnant, they assumed I wouldn’t pursue medical school. However, when I made it clear that I was, they flew out to Milwaukee and sat us down for ‘the big talk.’ They flat out said that we shouldn’t do this, that it would end up destroying our marriage, and so on. It was pretty intense. My father even argued that if I didn’t go to medical school, my husband wouldn’t have to sacrifice things in his life! But I must say, in the end, my parents did everything they could to help us, and they never brought it up again,” said Dr. Horowitz. “When I was in my early 50s, my father said, ‘Well, it seems to have worked out.’ My mother said that, after I graduated medical school, he showed the graduation program to everyone who walked into his office.”

Made for Each Other

Instead of the career-based discord Dr. Horowitz’s parents predicted, the young couple’s occupations meshed into a harmonic family dynamic. “Whoever was there did whatever had to be done. Moreover, my husband was the brother of professional women and came from a family where women were encouraged to follow their dreams. Being a teacher, my husband was usually home before me and had summers off, so he ran the home and took care of the kids, and he did it very well. So, it was smart of me to marry a teacher because, for one, I didn’t have to worry about child care,” said Dr. Horowitz.

In 1984, Dr. Horowitz earned her medical degree from the Medical College of Wisconsin, where she did her internal medicine residency and her hematology/oncology fellowship. “I’ve spent my entire career at the Medical College of Wisconsin, which, in my profession, isn’t the norm in that a lot of academic oncologists move as opportunities arise. Part of the reason I’ve remained at the College is compromise. My husband had a fantastic teaching job here, and we’d agreed that, as long as my career moved ahead, we’d stay in Wisconsin. As it turned out, I made the right decision because I have had such a great situation here that I never thought about leaving,” said Dr. Horowitz.

Serendipitous Journey to Oncology

Asked about her decision to pursue a career in bone marrow transplantation, Dr. Horowitz responded: “I wasn’t particularly drawn to oncology, but I wanted to be in academic medicine, a place where people asked questions and thought hard about finding the answers. However, after residency, when I took the job in general internal medicine at the Medical College, I had no research training to speak of. So, in 1985, I asked for protected time to do a master’s degree in biostatistics, so I could do my own clinical epidemiologic research. My advisor, the head of biostatistics, asked if I’d like to work on the bone marrow transplant registry database for my thesis. I said sure, and once I began, I fell in love with the field.”

“This, of course, introduced me to Mortimer Bortin, MD, the founding Scientific Director of the founders of the Center for International Bone Marrow Transplant Registry (CIBMTR) at the Medical College of Wisconsin (it was then the International Bone Marrow Transplant Registry). The CIBMTR maintains a large database with longitudinal clinical data on more than half a million transplant recipients, an extensive research repository, and a multifaceted research program that includes prospective clinical trials. Mort told me I was a natural and asked if I’d like to do this for the rest of my life. He was getting older and was looking for someone to take the reins, so I said, yes, I love this work, and, at this point in my career, I can’t think of anything else I would have rather spent my life doing,” said Dr. Horowitz.

After her decision to assume a leadership role in the CIBMTR, Dr. Horowitz, intent on maintaining a clinical connection to her work, did a 2-year oncology/hematology fellowship focused on bone marrow transplantation. “I’ve been a bone marrow transplantation clinical physician for my entire career. I actually succeeded Mort as the CIBMTR’s Scientific Director in 1991. After a wonderful and rewarding time, I just stepped down from that role in February of this year. I still head the national Blood and Marrow Transplant Clinical Trials Network and am also Deputy Cancer Center Director for the Medical College. In effect, I’ve passed the baton—to the very capable hands of Bronwen Shaw, MD, PhD,and a great leadership team. I’m a very firm believer in succession planning,” said Dr. Horowitz.

Advances in the Field

Dr. Horowitz noted that, over the arc of her career, the field of transplantation has markedly improved the outcomes of patients with hematologic malignancies and other blood disorders. “When I started, all of the patients were under 40, and the donors were HLA-matched siblings. The regimens were myeloablative, and although the outcomes were better than with conventional chemotherapy, they were still not very good. Now, two-thirds of transplants use autologous cells, which was a huge development that took place in the 1990s. And for patients who need an allogeneic donor, there is pretty much universal donor availability with ability to use HLA-mismatched related and unrelated donors and umbilical cord blood, with important innovations in preventing both graft rejection and graft-vs-host disease. Now, we do transplants in patients in their 70s, and the median age is mid-50s. Plus, a whole host of supportive care innovations have truly transformed the field. More advances are on the way. It’s an exciting time for the field.” She is also proud of the role that CIBMTR has played in that evolution—providing important analyses of “real-world data” long before that term entered the language of medicine.

Closing Thoughts

Dr. Horowitz continues to juggle several administrative and clinical roles as Professor and Deputy Cancer Center Director. “I am 66 and plan to work for another 4 or 5 years. As time moves on, one of my priorities will be in mentoring our young faculty. I really enjoy it and realize the importance of mentoring, having had terrific mentors who helped shape my career. One of my greatest pleasures is seeing a mentee succeed, having a paper published, or a grant accepted. It makes all the hard work worth it.”

How does a busy oncology leader decompress? “For me, family has been my escape, going to the kids’ school events and just spending time together. As they got older, our way to decompress was to travel—very often with our kids and grandkids. We have extended family all over the country, and we love international travel as well. Naturally, the past year has been a bit rough. Also, my wonderful husband is now pretty debilitated with frontotemporal dementia, a condition that has progressed for a decade. So, I spend a lot of time on his care. But spending time with friends and family is still my way to unwind—even if it has to be on Zoom. In the end, you have to know yourself, know what makes you tick, and how to control your time. People have asked me what I put first, my work or my family. I tell them it depends on the day. I’ve had a great career, and it’s not over yet.”