[1][2] He is most famous for his discovery, together with his colleague Joseph Fraumeni, of Li–Fraumeni syndrome, which is caused by germline mutations of the p53 tumor suppressor gene and genetically predisposes families to high rates of cancer.

[4] Li was born in Canton, China, and raised in New York City, where his parents operated a Chinese restaurant after World War II.

In 1996, Li was appointed by President Bill Clinton to NCI's National Cancer Advisory Board.

These young patients had a total of 50 bone and soft tissue sarcomas of diverse histological subtypes and 28 breast cancers.

The diversity of tumor types in this syndrome suggests pathogenetic mechanisms which differ from hereditary cancers arising in single organs or tissues.

The syndrome is presently diagnosed on clinical grounds; laboratory markers are needed to identify high-risk individuals and families and to provide insights into susceptibility mechanisms that may be shared by a wide variety of cancers.