House Foreign Affairs Chairman Tom Lantos (D-Calif.) announced Wednesday that he would retire from Congress at the end of this term after being diagnosed with cancer.

“Routine medical tests have revealed that I have cancer of the esophagus,” Lantos said in a statement. “In view of this development and the treatment it will require, I will not seek re-election.

Best known for his strong voice on human rights issues, the 79-year-old Lantos is currently in his 14th term in the House. His Bay area-based 12th district leans strongly Democratic and a competitive primary could ensue to replace him, as the winner of that contest almost will certainly cruise to victory in the general election.

Former California state Sen. Jackie Speier (D) already was contemplating challenging Lantos in the June 3 Democratic primary. State Sen. Leland Yee (D) also is thought of as a potential candidate, as is San Mateo County Supervisor Jerry Hill (D) and Millbrae City Councilwoman Gina Papan (D).

Speier could not be reached for comment Wednesday afternoon, and her spokeswoman, Nancy Parrish, was unable to provide an update as to when Speier might announce her 2008 candidacy for the 12th district. Speier has been putting together a campaign team and signaled that an announcement would come early this month.

Yee spokesman Adam Keigwin declined to comment on the state Senator’s interest in Lantos’ Congressional seat.

“It’s a little inappropriate to consider that right now,” he said. “[Yee’s] thoughts are with the Congressman and his family.”

Meanwhile, Hill and Papan are currently set to face each other in a Democratic primary for a seat in the state Assembly and there is some speculation that one or the other might find a run for an open House seat more attractive than a battle for a job in Sacramento.

Lantos spokeswoman Lynne Weil was unable to say Wednesday whether Lantos would eventually involve himself politically in the 12th district Democratic primary. Weil also declined to speculate as to how Lantos would spend his loaded war chest now that he is not running for re-election.

Lantos closed the third quarter of 2007 with $1.4 million on hand and will likely report even more than that in his fourth-quarter Federal Election Committee filing.