Dr. Mintz was a revered figure in the fields of genetics and cancer research, a scientist who stood out even among her most dedicated colleagues for the intensity she brought to her work and for the range and import of the advances it yielded.
She embarked on her career in the late 1940s, one of vanishingly few women pursuing scientific research at the time, and conducted her most significant studies at the institution that is now Fox Chase, where she arrived in 1960.
By the end of that decade, Dr. Mintz, an embryologist, had produced what became known as “multi-mice” — mice bred not from one mother and one father as in nature, but rather from the early embryos of numerous mice with differing characteristics, which she then observed in the offspring.
The animals were also known as “chimeric mice,” a term Dr. Mintz preferred to avoid because of its association with the monsters of Greek mythology. Her mice, which became the subjects of poetry she wrote in her free time, were not in the least monstrous, she found, and provided fundamental insight into the understanding of genetics and, in time, cancer.
“Recognizing that stem cells could generate a complete organism not only told us a lot about development,” Dr. Mintz told an interviewer at Fox Chase, “but also pointed to the possibility of using such cells to replace defective cells in humans.”
Dr. Mintz also did pioneering work in transgenesis — the introduction of genetic material from one organism into another — often using specialized needles and other equipment that she built herself.
“That same technology is still used to create models of all kinds of disease, not just cancer,” Jonathan Chernoff, the director of the Fox Chase Cancer Center, said in an interview.
In 1971, President Richard M. Nixon signed the National Cancer Act, marking the beginning of what became known as the “war on cancer.” The enemy in that war proved far more wily than many people had hoped, requiring the contributions of researchers across disciplines, among them genetics.
In an advance reported in the New York Times in 1979, Dr. Mintz showed that the cells of a particular kind of tumor, called a teratoma, could be inserted into a normal blastocyst, or early embryo, of a mouse. In a stunning development, the normal tissue reprogrammed the tumor cells so that they grew normally, and a healthy mouse was born.
“Most people thought that cancer cells were kind of dominant,” Chernoff said, and that they would grow without cease unless surgically excised or subjected to brutal courses of radiation or chemotherapy.
Dr. Mintz’s experiment, he said, showed that “you might be able to control cancer cells in a different way than poisoning them or burning them out,” thus helping open the way to a “less toxic approach to cancer.” Drugs that aim to similarly control tumors cells without killing them are today an emerging therapy for cancer, he added.
In the later years of her research career — which spanned well more than six decades — Dr. Mintz took on yet another challenge when she used transgenic technology to develop a mouse model for melanoma, a dangerous form of skin cancer. By inducing melanoma in mice, she allowed scientists to study the illness and pursue treatments with greater ease.
Taken together, Chernoff said, her discoveries were “foundational in more than one field.”
Beatrice Mintz was born in New York City on Jan. 24, 1921, to parents who were immigrants from Eastern Europe. When the family first came to the United States, her father earned a living ironing clothes in New York’s garment district.
“I came from a do-it-yourself family,” Dr. Mintz reflected, “and I enjoyed the fact that I had to work out everything myself.”
Dr. Mintz received a bachelor’s degree from Hunter College in New York in 1941 before pursuing graduate studies at the University of Iowa, where she received a master’s degree in 1944 and a PhD in 1946. She taught at the University of Chicago for 14 years before joining the Institute for Cancer Research, now Fox Chase, in Philadelphia.
In a practice unusual in modern science, Dr. Mintz used few laboratory assistants or postdoctoral fellows and chose to conduct her experiments and care for her mouse colonies on her own. One graduate student, Blanche Capel, now a professor of cell biology at Duke University School of Medicine, described Dr. Mintz in an email as “an extraordinary mentor who opened my eyes to the most important questions” in biology.
In addition to her poetry about mice, Dr. Mintz amassed a collection of what Chernoff described as “everything murine,” filling her office with photographs, sculptures and even tapestries of mice. She took one of her first experimental mice to a taxidermist, Chernoff recalled, an anecdote that he said he might have dismissed as “apocryphal” if he hadn’t seen the stuffed animal “with my own eyes.”
Dr. Mintz had no immediate survivors. Her honors included induction into the National Academy of Sciences, the first March of Dimes prize in developmental biology in 1996 (shared with geneticist Ralph L. Brinster) and the Szent-Györgyi Prize for Progress in Cancer Research, awarded by the National Foundation for Cancer Research, in 2011.
“Dr. Mintz’s scientific insights have led to new directions in developmental cancer biology and genetics,” Margaret Foti, chief executive of the American Association for Cancer Research, said when Dr. Mintz received the organization’s lifetime achievement award in 2012. “Her groundbreaking work has helped shape our understanding of stem cell behavior and the tumor microenvironment in cancer, and has provided scientists with important tools to study the many types of cancer.”
For her part, Dr. Mintz was said to have remarked that the most challenging questions of science were “the only ones worth considering.”