Viewer Question:

We have a family with prostate cancer. Five brothers are affected in one generation - otherwise there appears to be no sign of prostate cancer elsewhere in the family. Can anybody lend a hand in defining the cause of this cluster? Thank you.

Doctor's Response:

There are hereditary forms of prostate cancer. To put it in other words, there are genes that may make a man susceptible to prostate cancer.

One gene, for example, is called hereditary prostate cancer 1 (HPC1) or, alternatively, prostate cancer susceptibility 1 (PCS1). This gene is now known to be on chromosome 1, specifically in band 1q24-q25.

The genetic analysis of families with prostate cancer had originally indicated the existence of at least 1 gene for susceptibility to prostate cancer and predicted that high-risk alleles (gene variations) at such loci (spots) account for about 10% of all prostate cancers and for more than 40% of early-onset disease.

Genetic linkage studies were then done with both North American and Swedish families, each having at least 3 first-degree relatives with prostate cancer. By using over hundreds of distinctive DNA markers (called dinucleotide repeats), researchers were able to demonstrate genetic linkage between DNA markers in chromosome band 1q24-q25 and susceptibility to prostate cancer. This gene locus (location) was called HPC1 for hereditary prostate cancer 1.

It has been suggested that the potential ability to identify men at high genetic risk, when combined with physical exam, transrectal ultrasound, and prostate-specific antigen (PSA) analysis, could ultimately be of significant medical benefit.

However, genes at HPC1 appear to be responsible for only a minority of familial cases of prostate cancer and may be most important in families with at least 4 cases of the disease. There is now emerging evidence for a second gene locus, one on chromosome 10q25, that may also be associated with prostate cancer. The genetic story in prostate cancer is just beginning to unfold.