Women who are conceived when their father is overweight could be at a
high risk of developing breast cancer, new research suggests. The
findings, published online June 24 in Scientific Reports by Georgetown
Lombardi Comprehensive Cancer Center researchers, come from one of the
first animal studies to examine the impact of paternal obesity on future
generations’ cancer risk.
The researchers say they’ve found evidence that obesity changes the
microRNA (miRNA) signature – epigenetic regulators of gene expression –
in both the dad’s sperm and the daughter’s breast tissue, suggesting
that miRNAs may carry the epigenetic information from obese dads to
their daughters.
The identified miRNAs regulate insulin receptor signaling, which is
linked to alterations in body weight, and other molecular pathways that
are associated with cancer development. Epigenetics are heritable
chemical changes that can switch certain genes on or off. They are
increasingly becoming recognised as a mechanism that allows health
effects of the environment or lifestyle to be passed on to future
generations.
They work either by altering the protein that wraps DNA, adding or
removing chemical ‘tags’ that change the structure of cells, or via
genetic molecules. The study by Georgetown University Medical Centre was
carried out in lab mice but scientists said the findings applied to
humans.
“This study provides evidence that, in animals, a fathers’
body weight at the time of conception affects both their daughters’ body
weight both at birth and in childhood as well as their risk of breast
cancer later in life,” says the study’s lead investigator, Sonia de
Assis, PhD, an assistant professor in the department of oncology at
Georgetown Lombardi.
“Of course our study was done in mice, but it recapitulates recent
findings in humans which show that obese men have significant epigenetic
alterations in their sperm compared to lean men. Our animal study
suggests that those epigenetic alterations in sperm may have
consequences for next generation cancer risk.” de Assis says the next
step in this research is to see if the same associations regarding
breast cancer risk hold for daughters of human fathers who are
overweight around the time of conception.
“Until we know about this association in men, we should stick to what
we all know is good advice: women – and men – should eat a balanced
diet, keep a healthy body weight and life-style not only for their own
benefit but also to give their offspring’s the best chances of being
healthy.” According to the scientists, Obesity seems to sometimes run in
families, as do some breast cancers.
Maternal obesity is believed to influence both conditions in humans –
a woman who is heavy in pregnancy can produce larger babies, who may
have increased risk of breast cancer later in life. While much of the
focus has been on the maternal side, few if any studies have looked at
the influence of dad’s overweight and obesity on his offspring’s cancer
risk.
Breast Cancer has been reported as the number one Cancer killer of
Nigerian women. Although available health statistics in Nigeria are
largely unreliable, it is estimated that Breast Cancer is responsible
for about 16% of all cancer-related deaths in Nigeria. In another study,
researchers say the offspring of men who delay having children until
age 35 could be at risk of developing cancer later in life
A recent prospective study of more than 100,000 adult women in the
California Teacher’s Study has revealed an association between paternal –
but not maternal – age at birth and the risk of hematologic cancer, the
4th most common cancer in the U.S.
To further investigate the association, American Cancer Society
researchers led by Lauren Teras, Ph.D., analyzed data from women and men
enrolled in the American Cancer Society Cancer Prevention Study-II
Nutrition Cohort. The researchers found a strong, positive association
with paternal age among participants without siblings.
In that group, those whose fathers were aged 35 years or older at the
time of their birth were at 63 percent higher risk of hematologic
malignancies compared to those whose fathers were younger than 25.
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