Scientists have found strong evidence for inherited components in 12 different kinds of deadly cancers. This raises hope for earlier detection and better targeting of therapy. While the new study confirms the role of inherited genes in breast and ovarian cancer, the surprising discovery was that even stomach cancer has an evident link with genes passed down from parents.
Other types of cancer analysed in the study included those found in prostate, lungs, brain and nervous system, uterus, blood, etc.
“In general, we have known that ovarian and breast cancers have a significant inherited component, and others, such as acute myeloid leukemia and lung cancer, have a much smaller inherited genetic contribution,” said senior author Li Ding of the McDonnell Genome Institute at Washington University. “But this is the first time on a large scale that we’ve been able to pinpoint gene culprits or even the actual mutations responsible for cancer susceptibility.”
The study was carried out by researchers from several US universities including Washington University, St.Louis, Ohio State University, Brown University and Medical College Wisconsin. It was recently published in the scientific journal Nature Communications.
Scientists have found that 114 genes are linked to cancer. Defects in these genes can increase cancer risk. But it was not known whether the defects arose during the patient’s life or it was passed on from parents. In this new study, the inherited defects were teased out by the researchers.
Analysis of the 12 types of cancers showed that the occurrence of inherited defects increased in the affected areas indicating a direct link with the disease. Such increases were found most in ovarian (19%) and breast cancers (9%) but also in stomach (11%), prostate, one type of lung cancer, glial and head and neck cancers (all 8%). On the other hand, inherited component was weak in acute myeloid leukemia (a common blood cancer) and glioblastoma (a common brain cancer).
An additional discovery was that the gene usually linked to breast and ovarian cancer in women seemed to have a role in other types of cancer too. The defect associated with this gene was found with increased concentration in other cancers.
In India, the five most common types of cancer in men are mouth, lung, stomach, bowel and throat, while among women they are breast, cervix (lower uterus), bowel, ovary and mouth.
All this has clarified the genetic links of cancer somewhat but a lot more needs to be found out, the researchers say. Genes interact with each other in very complex and confounding ways and to pinpoint cause and effect is very complicated. This research is a big step towards eventually having a database of all mutations (genetic changes) that are linked to different types of cancer so that preventive screening can be done.