Dr. John Mendelsohn, the face of Houston's revered University of Texas M.D. Anderson Cancer Center, will retire as its president next summer, according to an e-mail he sent to employees on Monday.

In its own statement, M.D. Anderson downplayed the "r" word, instead calling Mendelsohn's departure as president a role change.

Mendelsohn will remain a member of the cancer center's faculty as co-director of the new Institute for Personalized Cancer Therapy. He will also return his focus to research on targeted cancer therapies, one of the technologies he helped bring to M.D. Anderson and established as an area of great expertise. The IPCT will focus on targeting the abnormal genes and products of genes that cause cancer and tailoring treatment for individual patient needs.

"I'm not hunting for free time," Mendelsohn told CultureMap. "I like building things and working with talented teams. It's a smaller level of responsibly, and maybe I'll have a little more time to look into hobbies and visit with family and things like that, but it's not retirement. It's switching focus."

Mendelsohn has overseen rapid expansion of the cancer center during the nearly 15 years he has served as president. It now employees nearly 18,000 people and occupies 11.5 million square feet in the Texas Medical Center. It serves more than 100,000 patients each year with a budget of more than $3.2 billion. During the last decade, M.D. Anderson has more than doubled its size and number of clinics.

Under Mendelsohn's tutelage, the center has been named the leading cancer hospital in the nation six out of the past eight years in U.S. News and World Report's America's Best Hospitals survey.

The 74-year-old doctor wrote in his e-mail that he viewed his new positon at the IPCT as a return to his roots, and said it was "truly the culmination of my life-long dream."

Mendelsohn said he has high expectations for M.D. Anderson's continued success, and offered some advice to his eventual successor. "The person can expect to be very stimulated and have many challenges, and in addition to addressing the usual things there will be an extra agenda, and that will be helping to figure out how to move M.D. Anderson into the new way healthcare is being delivered and paid for in the U.S. in the next 5 years."

Mendelsohn came to M.D. Anderson from New York's Memorial Sloan-Kettering Cancer Center in 1996. He is only the third president to head M.D. Anderson since its founding in 1941.

He is expected to retire as president by Aug. 31, 2011. A search committee for his replacement will likely begin their efforts in January.