SAN FRANCISCO — Former Arizona governor Janet Napolitano has been hospitalized with complications from her cancer treatment.

Napolitano is a former U.S. Homeland Security secretary and currently president of the University of California. On Tuesday, the school system revealed her hospitalization and that she has been undergoing cancer treatment for five months.

The UC Office of the President said Napolitano, 59, was diagnosed last August but did not say what type of cancer she has or respond to inquiries seeking further details. Her condition was never made public and emerged only after a side effect from her medication sent her to the hospital Monday.

Her office said Napolitano has performed her duties at full capacity and is expected to be discharged in the next day or so. The president of the 10-campus system has kept the chairwoman of the UC Board of Regents informed throughout her treatment, which is nearly complete, the university said.

Napolitano, who previously was treated successfully for breast cancer, was a two-term Democratic governor of Arizona before joining President Barack Obama's Cabinet.

She served as secretary of the Department of Homeland Security from 2009 to 2013, as governor of Arizona from 2003 to 2009, as Arizona's attorney general from 1998 to 2003, and as U.S. attorney for Arizona from 1993 to 1997.

Napolitano now oversees the 10 UC campuses, five medical centers, three affiliated national laboratories, and a statewide agriculture and natural resources program.

In November 2004, Napolitano had surgery to remove her right ovary and an ovarian cyst, which was benign. She resumed a normal work schedule three days later.

Napolitano had her right breast removed in 2000 after being diagnosed with cancer.