University of California President Janet Napolitano (Jeff Chiu/Associated Press)

University of California President Janet Napolitano has been diagnosed with cancer and was hospitalized this week after experiencing side effects related to her treatment, the UC system disclosed Tuesday.

A former U.S. secretary of homeland security and governor of Arizona, Napolitano previously underwent a successful treatment for cancer. She received her second cancer diagnosis in August and has been undergoing treatment since then, UC Office of the President said in statement.

The statement did not disclose the type of cancer Napolitano has. It said her treatment is nearly complete.

“During the course of this treatment, President Napolitano has consistently performed her wide range of duties at full capacity, without interruption or impact,” the statement said. “Yesterday, however, she experienced side effects that required her to be hospitalized.”

“According to her physicians, she is doing extremely well,” it continued. “They expect her to be discharged in the next day or so and back to her normal duties at full capacity very soon. While she is recuperating, UC’s senior leadership will continue to support President Napolitano in the management of the UC system and in advancing the university’s key priorities.”

Napolitano was President Obama’s first secretary of homeland security. She has been president of UC since September 2013. She oversees a world-renowned public higher-education system, with 10 campuses, five medical centers and three affiliated national laboratories. The system has 238,000 students and more than 190,000 faculty and staff.