John Stewart from Cambridgeshire was an active man in his forties, when he was struck down by prostate cancer.
Since his death two years ago, his wife and two daughters have raised more than £100,000 for the charity Prostate Cancer UK.
As Fathers' Day approaches they are calling on other families to make sure the men in their lives go to the doctor - to get themselves checked out before it's too late, as Elodie Harper reports.
Prostate cancer is predicted to become the biggest cancer killer by 2030, which means men going to have a check up is becoming more and more vital.
Emma Baker spoke to Meg Burgess, a nurse with Prostate Cancer UK, who explains thats the disease isn't always easy to spot.