Healthy lifestyle may help mitigate high genetic risk of cancer

Date:
July 28, 2021
Source:
American Association for Cancer Research
Summary:
Healthy lifestyle factors such as abstinence from smoking and
drinking, low body mass index, and exercise correlated with
decreased cancer incidence, even in individuals with a high
genetic risk.



FULL STORY ========================================================================== Healthy lifestyle factors such as abstinence from smoking and drinking,
low body mass index, and exercise correlated with decreased cancer
incidence, even in individuals with a high genetic risk.


==========================================================================
As genetic research continues to uncover loci, or areas in DNA,
with specific changes that influence cancer risk, researchers can
define polygenic risk scores (PRS) -- personalized estimates of an
individual's cancer risk -- based on a patient's unique combination of
these changes. However, most PRS are generated for a specific cancer type, rather than for overall cancer risk.

"A PRS indicating risk of a certain cancer is important but not enough,"
Jin said. "We tried to create an indicator -- the cancer polygenic
risk score (CPRS) -- to measure the genetic risk of cancer as a whole."
Jin and colleagues calculated individual PRS for 16 cancers in men and
18 cancers in women, using available data from genome-wide association
studies.

They then used statistical methods to combine these scores into a single measure of cancer risk, based on the relative proportion of each cancer
type in the general population. Separate CPRS were generated for men
and women.

To validate their CPRS, the researchers utilized genotype information
from 202,842 men and 239,659 women from the UK Biobank, a cohort of
general- population participants recruited from England, Scotland, and
Wales between 2006 and 2009, and calculated a CPRS for each individual.

UK Biobank participants were surveyed upon enrollment for various
lifestyle factors, including smoking and alcohol consumption, body mass
index, exercise habits, and typical diet. Based on these factors, Jin
and colleagues classified each patient as having an unfavorable (zero
to one healthy factors), intermediate (two to three healthy factors),
or favorable (four to five healthy factors) overall lifestyle.

Patients with the highest quintile CPRS were nearly twice as likely
(for men) and 1.6 times as likely (for women) to have a cancer diagnosis
by their most recent follow-up, in 2015 or 2016. Notably, 97 percent of patients in the study had a high genetic risk (top quintile) of at least
one cancer type. "This suggests that almost everyone is susceptible
to at least one type of cancer," Jin said. "It further indicates the
importance of adherence to a healthy lifestyle for everyone." Patients
with an unfavorable lifestyle and the highest quintile genetic risk were
2.99 times (in men) and 2.38 times (in women) more likely to develop
cancer than those with a favorable lifestyle and the lowest quintile of
genetic risk.

Among patients with high genetic risk, the five-year cancer incidence
was 7.23 percent in men and 5.77 percent in women with an unfavorable lifestyle, compared with 5.51 percent in men and 3.69 percent in women
with a favorable lifestyle. The decreased percentages are comparable
to the cancer risk in individuals with intermediate genetic risk,
Jin said. Similar trends were observed in all genetic risk categories, suggesting that patients could benefit from a healthy lifestyle regardless
of genetic risk.

Limitations of this study include the fact that only the strongest
genetic risk loci were included in the individual PRS, which disregards
the influence of loci with weaker effects. Researchers also noted an
imbalance in the number of loci included between different cancer types,
which can potentially skew their individual impact.

========================================================================== Story Source: Materials provided by
American_Association_for_Cancer_Research. Note: Content may be edited
for style and length.


========================================================================== Journal Reference:
1. Meng Zhu, Tianpei Wang, Yanqian Huang, Xiaoyu Zhao, Yuqing Ding,
Mengyi
Zhu, Mengmeng Ji, Cheng Wang, Juncheng Dai, Rong Yin, Lin
Xu, Hongxia Ma, Qingyi Wei, Guangfu Jin, Zhibin Hu, Hongbing
Shen. Genetic risk for overall cancer and the benefit of adherence
to a healthy lifestyle.

Cancer Research, 2021; canres.0836.2021 DOI:
10.1158/0008-5472.CAN-21- 0836 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/07/210728105633.htm

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