Sen. Miriam Defensor-Santiago gives her opening statement during the 3rd PiliPINASDebates2016 at the PHINMA Univeristy of Pangasinan in Dagupan City on Sunday. Fernando Sepe, Jr., ABS-CBN News

MANILA (2nd UPDATE) - Senator Miriam Defensor Santiago, who has been battling lung cancer, is now in a hospital's intensive care unit (ICU), her husband announced Wednesday.

According to Narciso "Jun" Santiago, the 70-year-old senator suffered a complication and was rushed to the Makati Medical Center (MMC) on Monday.

On Tuesday evening, she was transferred from her private room to the ICU.

Jun said his wife "is bearing well with her trademark sense of humor."

READ: Narciso 'Jun' Santiago, Miriam's shock absorber

Visitors are not allowed and gifts, including flowers, will not be accepted, he said.

"Miriam said that she thanks all her family, friends, supporters, fans, and others who helped pray for her recovery and sent their well-wishes on Facebook," the statement read.

It was in July 2014 when the feisty senator announced that she had been diagnosed with stage 4 lung cancer.

In October 2015, she claimed having "conquered" the disease and announced her intention to seek the presidency for the third time.

READ: Miriam: 'I will never quit!'

While she repeatedly dismissed doubts on her health, Santiago was not very visible in the campaign trail with her running mate, Senator Ferdinand "Bongbong" Marcos Jr.

She even failed to attend the second presidential debate on March 20 because she underwent clinical trial for a new anti-cancer pill.

Santiago attended the third and final debate and stuttered at times but tried to show strength, as she answered questions and presented her platforms.

Santiago lost in the recently concluded May 9, 2016 elections, placing last in the presidential race dominated by Davao City Mayor Rodrigo Duterte.

READ: Miriam Santiago on election loss: That's life

Just two weeks after the polls, Santiago sent a notice to the Senate saying she would extend her medical leave.

She said one of her anti-cancer medications caused a side effect, anorexia or inability to eat, rendering her "physically and mentally weak."

READ: Miriam's anti-cancer meds causing anorexia

Santiago will step down as senator on June 30 after two consecutive terms.

WELL-WISHES

Meanwhile, some of Santiago's colleagues in the Senate, including her running mate, have sent their well-wishes, hoping for her immediate recovery.

"Senator Santiago has proven to be a relentless fighter against corruption and incompetence in government all throughout her career. It is our hope that she again wins this fight and be on her way to full recovery," Marcos said in a statement.

"Get well soon. My prayers are with you," Senator Grace Poe, one of Santiago's rivals in this year's presidential race, said in a Twitter post.

Senator Nancy Binay likewise prayed for Santiago's fast recovery. "Despite her illness, she has shown us that serving the country still comes first," Binay said.