Cantoni was working for Care International when she was kidnapped in Kabul three weeks ago.
"Our hope is the last thing that we are going to give up," Beatrice Spadacini, a spokesperson for Care International, said at a vigil for Cantoni in Kabul on 6 June. "We have it, and I hope that every one is working really hard to get her back."
At the vigil, dozens of colleagues and friends of Cantoni lit a torch symbolizing their hope that she will be freed soon.
The Italian ambassador in Kabul, Ettore Sequi, said his government and the Afghan government are committed to getting Cantoni back safely.
"It is very important that we are here now today with this fire which represents the fire of our commitment and the fire of our hope and the fire of our engagement to work together in solving as soon as possible this case," Sequi said.
Cantoni, 32, was abducted on a Kabul street on 16 May by four gunmen. She had been living in Afghanistan for three years working on aid projects to help the poor.
Muslim clerics and scholars, as well as politicians, have called for the hostage takers to set Cantoni free. But so far to no avail.
The Italian daily "La Republicca" reported on 5 June that Afghan and Italian negotiators had come close to freeing Cantoni three times in the last few days.
But the paper said the talks broke down at the last minute.
Little is known about the group that abducted Cantoni.
Afghan officials have said they believe her kidnappers are criminals, not Taliban or allied Islamic militants. But the government has not revealed what demands the hostage takers are making in their negotiations or who the hostage takers are.
"We, the widows, request from our brother kidnappers to release her as soon as possible. She was the one giving food to our orphan children. Because of that, please, release her."
An Afghan television station broadcast a video of Cantoni late last month showing her flanked by two masked men pointing assault rifles at her.
Cantoni had been managing a project in Kabul which provides food and income-generating activities for 11,000 widows and their children since September 2003.
Some of the widows she has helped appealed for her release during a rally in Kabul on 5 June.
"We, the widows, request from our brother kidnappers to release her as soon as possible," said Jamela Jan, one of the women attending the rally. "She was the one giving food to our orphan children. Because of that, please, release her."
Another widow, Shah Gul, made a similar plea. "She helped us for the past three years. During the past three years, I did not feel that I was a widow. But since she was kidnapped, I feel that I am a widow because she was giving food to my children."
The kidnapping has raised widespread alarm among the some 2,000 foreign aid workers in Kabul.
It comes after three UN workers were released unharmed by militants in November after four weeks of captivity.
The Afghan government declined to identify the suspected kidnappers in that case or to explain how the hostages were released, except to say no ransom was paid.