Men do not have ovaries, but they can pass the risk of ovarian cancer to their daughters. It is done through a new gene mutation inherited via the X-chromosome, BBC reported.
Experts, however, declined to confirm the identity and function of the gene until more studies are made. Ovarian cancer and breast cancer can also be passed through the BRCA gene via women with a strong family history of cancer.
Hollywood actress Angelina Jolie inherited BRCA1 from her mother. After doctors placed her chance of breast cancer at 87 percent and ovarian cancer risk at 50 percent, she underwent preventive surgery.
One of the suspect genes is the MAGEC3. But Kevin Eng, from the Roswell Park Cancer Institute, said that they have to first ensure that they have the right gene by sequencing more families. He said the findings led to a lot of discussion within their group on how to find the X-linked families.
They observed that ovarian cancer linked to DNA from the father and paternal grandmother had an earlier age of onset than those linked to the genes of the mother. The unidentified gene mutation was also associated with higher rates of prostate cancer in fathers and sons.
Eng said that the gene mutation has an all-or-none kind of pattern. He explained that a family with three daughters who have ovarian cancer have a higher chance of inheriting the X mutations than by BRCA mutations. Because of the newly discovered faulty genes, the study suggested that the ovarian cancer risk of some women could be passed through the father's family and mother's family.
Dr. Catherine Pickworth from Cancer Research UK said that in the future, the research could help women with a family history of ovarian cancer to have a better understanding of the ailment. It is important because ovarian cancer is often diagnosed at a late stage when it is harder to treat. But to get a clearer picture of how the genetic faults uncovered in the study might affect the inherited risk of ovarian cancer, more studies are needed.
Reducing mortality risk
The findings were the result of a review of the results of an assessment of the findings of over 1,000 research papers published between 2003 and 2017 in JAMA to establish if screening reduces mortality risk for women who do not have a hereditary risk for ovarian cancer.
The study, published in PLOS Genetics journal, concluded that the harms of ovarian cancer screening outweighed the benefits for women in the average risk category. But the researchers also identified a new genetic mutation associated with early-onset ovarian and prostate cancer inherited through the father's X chromosome, Medical News Today reported.
The researchers were led to explore if DNA passed down by the father of ovarian cancer patients boosted their risk of cancer after past research observed that the sisters of ovarian cancer patients seem to have a higher risk of developing that type of cancer than their mother.
The scientists used the Familial Ovarian Cancer Registry resource, based at Roswell Park and funded by donors, to examine data on pairs of granddaughters and grandmothers. The results showed that cases of ovarian cancer linked with genes inherited from the paternal grandmother were more strongly associated with early-onset cancer than those linked with genes passed to patients from their mother.
When the researchers sequenced parts of the X chromosome from 186 people with ovarian cancer, they found that a previously unidentified mutation is linked to an increased risk of ovarian cancer. Those cases developed more than six years earlier that the average age of onset of ovarian cancer.
Eng said that the study explains why families have multiple affected daughters. It is because a father's chromosomes determine the gender of his children. All of his daughters have to carry the same X chromosome genes.
The study shows how much science still has to learn about how genetics influences the risk of cancer, Dr. Avner Hershlag, the chief of Northwell Health Fertility in New York, said. He noted that the genes so far discovered are just the tip of the iceberg. Hershlag said that together, the group of genes will compromise a much higher percentage of cancer causes, Healthline reported.
He underscored the value of doctors providing more information to their patients about their cancer risk so the physicians can be there for them before and after a cancer diagnosis. The diagnosis means a lot in terms of how the patients will manage the rest of their lives and the kind of preventive or prophylactic monitoring they will do.
Fertility doctors can test embryos for certain genes to ensure it is not passed on to the next generation, but if the gene has not been identified, physicians cannot help, Hershlag said.
[researchpaper 리서치페이퍼=Vittorio Hernandez 기자]