Which family member's prostate cancer history significantly raises a man's risk?

A brother's history of prostate cancer significantly raises a man's risk because prostate cancer is known to have a hereditary component. The presence of prostate cancer in a close male relative, such as a brother, suggests that there may be shared genetic factors that increase susceptibility to the disease. This familial relationship is crucial in assessing risk, as close male relatives offer the strongest evidence for genetic predisposition in conditions like prostate cancer.

In contrast, the influence of prostate cancer history from other family members, such as a mother, sister, or aunt, is generally less pronounced due to the different inheritance patterns and the typically lower risk associated with female relatives in terms of affecting male cancer risk. The male-to-male transmission of hereditary factors directly associated with prostate cancer makes a brother’s diagnosis a more significant risk marker.