deCODE’ing Predisposition to Cancer November 17, 2007Posted by ramunas in breast cancer, cancer genetics, colon cancer, deCODE, genetic testing, prostate cancer.
Today launched personal genomics service of Icelandic company de CODE – deCODEme – totally surprised me. That was a smash for 23andMe and Navigenics, I think. For a promotional price for the Genetic Scan for $985 (plus sales tax / VAT) users can receive a bunch of information regarding personal genome variation, or SNP’s (discovered mainly in companies own studies and replicated by others), which can predispose to as much as 17 common disease (colorectal, prostate and breast cancers included), eye color, your hair color and many other physical attributes and also discover the origin of ancestry. Wow, kind of social-genomic-network!
I’ve jumped inside deCODEme portal, and will briefly summarize oncological side of this service (disclaimer: most of the text bellow can be found inside deCODEme portal after logging).
The deCODEme genome scan test for these common genetic variants related to these onco-disease:
- Breast cancer. It includes the variants on chromosomes 2 and 8, as well as those in the FGFR2, the TNRC9/TOX3, the LSP1, the MAP3K1 and the CASP8 genes and interpretation of their associated risk to the development of breast cancer.
Note: Strongly acting mutations (like in BRCA1/2 genes) comprise a small percentage of breast cancer cases (2-5%). Variants that are more common but carry less risk play a role in a much larger proportion of cases, perhaps in almost all breast cancer cases. Such variants may individually be quite common with each one alone having little effect on breast cancer risk. However if a person inherits many of these variants, the risks from them might combine to produce a substantial increase in the individual’s overall risk. Combinations of these common breast cancer risk variants may or may not show up as an obvious family history of breast cancer.
Note: It has been estimated that up to 30% of colorectal cancers may be due to genetic factors. A fraction (~5%) of colorectal cancer cases occur in families with multiple cases of the disease and appear to be inherited in a dominant manner. An example of such condition is multiple polyposis of the colon, where the inner surface of the colon is covered with thousands of polyps. These cases are in some instances known to be caused by specific mutations in genes that increase the risk of the disease substantially (up to 100%). Individuals belonging to such families should seek counselling about preventive measures. The deCODEme genome scan does not include the rare highly familial cancer genes such as APC, MLH1, MSH2, MSH6, and PMS2. Variants that are more common, but confer less risk, play a role in a much larger proportion of colorectal cancer cases. Such variants may individually be quite common with each one alone having little effect on the colorectal cancer risk. However if a person inherits many of these variants, the risks from them might combine to produce a substantial increase in the individual’s overall risk. To date two common genetic variants have been found that increase the risk of developing colorectal cancer. These are variants on chromosome 8, not close to any known gene, and in the SMAD7 gene on chromosome 18.
- Prostate cancer. Includes the three variants from the 8q24 region and the two from chromosome 17 and an interpretation of their associated risk of developing prostate cancer.
Note: Prostate cancer has been shown to have the strongest genetic component of all cancers. To date several genetic variants have been discovered to increase the risk of developing prostate cancer. These are three variants in the chromosome 8q24 region that lacks any know genes, and two on chromosome 17, one of which is in the TCF2 gene.
Other reviews (updated):