Two of Canada's richest families made significant donations to the fight against cancer Monday, boosting Toronto-area centres that conduct breast cancer research and treat cancer patients.

Descendants of late newspaper magnate Roy Thomson donated $25 million for breast cancer research, in what is thought to be the single largest gift for cancer research in Canadian history.

Thomson's daughter, Audrey Campbell, and her three daughters made the donation to the Institute for Breast Cancer Research at Toronto's Princess Margaret Hospital on Monday.

In return, the research facility will be named the Campbell Family Institute for Breast Cancer Research. The funding will enable the institute to double the number of its personnel, to 162.

The institute's director, acclaimed researcher Dr. Tak Mak, called the donation a "significant and visionary gift to breast cancer research."

The man who would become the 1st Baron Thomson of Fleet was born in 1894 in Toronto, the son of a barber.

He started his newspaper chain with a $200 downpayment for The Timmins Press in 1934.

The business grew to include more than 200 newspapers in Canada, the United States and the United Kingdom, with interests in publishing, television, and travel.

In another announcement Monday, car parts entrepreneur Frank Stronach donated $8 million to a fund that will build a cancer centre in Newmarket, north of Toronto.

The centre, to be named the Stronach Regional Cancer Centre-Magna Building, is scheduled to open in 2007. It will complement the nearby Southlake Regional Health Centre.

"At Magna, we believe we have an obligation to support the basic fabric of society by donating a portion of our annual profits to charitable, education and health causes," Stronach, the chairman of Magna International, said in a news release. "We are fortunate to be able to give back to the community where so many of our employees live and work."