Rep. Juanita Millender-McDonald (D-Calif.), 68, who'd taken leave from Congress after being diagnosed with cancer, died Sunday, a congressional source said.

House Clerk Lorraine Miller has secured Millender-McDonald's office and is to oversee the office until an election can be held to replace her.

Rep. Robert Brady (D-Pa.) had indicated he would assume interim leadership of the House Administration Committee during Millender-McDonald's leave.

He is a candidate in the crowded race to become the next mayor of Philadelphia. Rep. Chaka Fattah (D-Pa.) is one of the five other candidates in the race.

Millender-McDonald had been serving her seventh term in Congress. She was the first African-American woman to chair the House Administration Committee. She has five children and several grandchildren.

The chair of the House Administration Committee’s is sometimes referred to as the Mayor of Capitol Hill. The position confers authority over salaries and expenses for committees and staff, the Franking Commission, benefit and retirement structures, and many other administrative issues.

She is the second member of Congress to die of cancer this year. The first was Rep. Charles Norwood (R-Ga.).

Millender-McDonald's Long Beach-based district is solidly Democratic. In 2004 Democrat John Kerry got 74 percent to President Bush's 25 percent.

According to the Almanac of American Politics, she has easily won re-election in the past. In the 2002 primary, she beat Peter Mathews, 78 percent to 22 percent. In 2004, Mathews challenged her again and lost the primary 65 percent to 16 percent. Millender-McDonald easily won the general each time.