Who is Frank Burnet from Next and what is their importance?

Frank Burnet is a construction worker who developed cancer in middle age. Burnet sought treatment and survived his cancer despite being told he would not. A time after Burnet has been told his cancer is in remission, he goes to the doctor for routine follow up tests. Shortly after these tests, Burnet's doctor calls him and asks to run more tests. The doctor does not tell Burnet what these tests are for. However, Burnet is routinely called in for more of these tests. Burnet comes to believe that his cancer has returned.