Justice Margaret Cameron began work Tuesday on a judicial inquiry into botched breast cancer tests affecting hundreds of patients in Newfoundland.

Cameron, the province's first female Supreme Court judge, is charged with investigating how and why 317 patients under Eastern Health Authority received the wrong cancer screening results.

The government announced the judicial inquiry in May after it was found the error rate of hormone receptor tests was much higher than thought.

"We are committed, through this process, to ensuring that the public's confidence in this area is restored and that all necessary details are disclosed in an open and transparent manner," Premier Danny Williams said during a June 14 session in the legislature.

Williams has assured there will be no political interference during the inquiry process.

In 2005, the Eastern Health Authority arranged for Mount Sinai Hospital in Toronto to redo more than 2,000 hormone receptor tests going back to May 1997 after oncologists discovered inconsistent results in breast tumour samples.

Hormone receptor tests are used to help determine which type of treatment a breast cancer patient should receive.

Test results became available to Eastern Health between October 2005 and February 2006.

The authority notified 117 patients whose treatment was changed, but the remainder of the 317 total was not informed.

At least 26 of the women who received the wrong test results have died, although it's unclear whether their deaths were directly related to their cancer.

In May, George Tilley, CEO of the Eastern Health Authority, apologized saying the larger scope of the problem should have been revealed earlier.

"I regret the decision that we didn't simply refer to it earlier,'' he told a news conference."And I apologize for the confusion that that caused.''

About 100 patients have since filed a class-action lawsuit against the health authority.

Cameron is expected to deliver her final report on July 30, 2008.

With files from the Canadian Press