Common Genetic Forms for Different Cancers

Prostate, Ovarian and Breast Cancers May Be Linked

Nov 24, 2008

Twelve genetic variants, also called single nucleotide polymorphisms, known as risk factors of prostate cancer, have also been analyzed in ovarian and breast cancers.

It is already well known that certain forms, or mutation, of particular genes may confer a susceptibility to specific cancer. For example, a woman, carrying a certain form of BRCA1 or BRCA2 genes, has an 80% chance of developing ovarian or breast cancer in her life time. Another example is the APC gene in colorectal cancer or the PTEN gene in prostate cancer.

Although mutated BRCA genes is a high risk of familial cancer, they are present in only 40% of familial ovarian cancer and less than 25% of familial breast cancer risk. It is likely that other genes also confer some inherited risk of ovarian and breast cancer. It is also suspected than certain genes may confer a risk to more than one type of cancer.

British Researchers Analyzed Genetic Prostate Cancer Risks in Ovarian and Breast Cancer

A British team of researchers, supervised by Dr Paul Pharoah, from University of Cambridge (Cambridge, United kingdom), has reanalyzed 12 genetic variants, previously identified as risk factors of prostate cancer, in the context of ovarian, breast and colorectal cancers. Their results, entitled `Association study of prostate cancer susceptibility variants with risks of invasive ovarian, breast and colorectal cancers are published in the scientific journal Clinical cancer Research (Cancer Res 2008;68(21):8837-42).

Two Genetics Prostate Cancer Risks Are also Ovarian and Breast Cancer Risks

The 12 prostate cancer-associated genetic variants also called SNP (single nucleotide polymorphisms), were analyzed in more than 2000 ovarian cancer patients and 4000 breast cancer patients, as well as 2000 colorectal cancer patients.

Out of 12, only one genetic variant (rs5945619) in the chromosome X, was also weakly associated with ovarian and breast cancers. Another genetic variant, rs2660753 on chromosome 3, near the VGLL3 gene, was associated with increase ovarian cancer risk only, while the genetic variant rs7931342, on chromosome11, was associated with a breast cancer protection. No association was observed with colorectal cancer risk.

The scientists, however, highlighted also the fact ththese results, should to be treated with caution: ″A large number of reported positive associations have not been replicated by subsequent studies. In the (scientific) literature, it has been estimated that the fraction of false-positive findings is at least 0.95 for studies of association between genetic variants and disease risks″. The reason is that common genetic variants are shared in the population and may be present in a group of people without any link to disease. Such genetic studies need to be reproduced in large independent population of patients.

Common Genetic Basis With Prostate and Ovarian or Breast Cancer

Assuming these results are true, they support the fact that common genetic basis for prostate, ovarian and breast cancer may exist and that ovarian or breast cancer patients are more likely to have a first-degree relative with prostate cancer.

The copyright of the article Common Genetic Forms for Different Cancers in Human Genetics is owned by Cecile Le Page. Permission to republish Common Genetic Forms for Different Cancers in print or online must be granted by the author in writing.