Prostate cancer is thought to be the most heritable cancer. Positive family history is consistently associated with a 2- to 4-fold increased risk of the disease. Family and twin studies can demonstrate the importance of genetic and environmental factors in explaining the differences in the likelihood of developing prostate cancer.
Researchers undertook the world's largest prospective study in the Nordic Twin Study of Cancer cohort, including 18,680 identical (monozygotic, MZ) and 30,054 fraternal (dizygotic, DZ) same-sex male twins. They incorporated time-to-event analyses to estimate risk and heritability of prostate cancer.
For men whose co-twin was diagnosed with prostate cancer, the risk of developing prostate cancer was 3-fold greater for identical twins than for fraternal twins across all ages. The time between diagnoses was shorter for identical twins than fraternal twins (3.8 vs. 6.5 years). For fraternal twins, the lifetime probability of developing prostate cancer if the co-twin had cancer was 1 in 5, which is almost twice the lifetime risk in the general population.
The study also found that the heritability for prostate cancer was 58%, higher than was previously believed. This suggests that genetics contributes more to the risk of developing prostate cancer than environmental factors.
Hjelmborg A., et al. The Heritability of Prostate Cancer in the Nordic Twin Study of Cancer. Cancer Epidemiol Biomarkers Prev. 2014; 23(11):2303-10.