Exposure to diethylstilbestrol during sensitive life stages: a legacy of heritable health effects
The legacy of the adverse effects that stem from DES administration to pregnant women in the 1950s to 1970s has not completely formed. The male and female offspring of those women have reported significant fertility, cancer, and birth-related outcomes, but the cancer outcomes are not completely understood, with few exceptions (CCA and breast cancer in women over 40 yr old).
Information on DES mothers and daughters, in addition to substantial animal data, earned DES a place in the First Annual Report on Carcinogens, a critical review of carcinogenic compounds produced by the National Toxicology Program, in 1980 and was noted by the International Agency for Research on Cancer in their Monographs (IARC 1974). As the male and female offspring of those women age, the overall effect of DES on reproductive cancers will be better understood. Even more important to understand is the potential effect of this endocrine disruptor and carcinogen on the 3rd generation offspring who were not directly exposed, but may be affected in a heritable way through estrogen reprogramming and DNA modification.
Further research is needed to indicate the mechanisms of action on the target tissues, so that future pharmaceuticals/environmental estrogen mimics will avoid these pathways, leading to healthier future generations. Future studies should focus on common target tissue pathways affected and the health of the DES grandchildren.
Walker and Haven (1997) predicted that “if the high intensity of DES multigenerational carcinogenicity seen in mice is applicable to the human population, this is a health problem of major proportions.” They go on to say that it “could take over 50 years” to detect the effects in future generations, due to the length of time required for diseases such as cancer to manifest. It is predicted that cross-generational responses to DES exposure are possible due to epigenetic changes in the DNA and that the “germ cell pool could have become massively contaminated”. For example, early exposure to EDCs, like DES, is thought to reprogram mouse female reproductive tract development and affect how the reproductive tract responds to endogenous estrogens later in life (Ma 2009; Hilakivi-Clarke et al., 2013). They (Walker and Haven 1997) suggest that “environmental estrogens may be more potent than previously suspected, due to synergistic action from concurrent exposures.”
The studies on the cohort of men (grandsons) and women (granddaughters) whose mothers were exposed prenatally to DES (grandchildren had no direct exposure) are limited as they are just beginning to reach the age when relevant health problems can be studied (CDC 2012). Studies that have been performed contain preliminary data, as the power is low. Therefore, the main sources of information for third generation effects are rodent studies. In general, multi-generational mouse studies have shown an increased susceptibility to tumor formation in the third generation which suggests that DES grandchildren are also at an increased risk for cancer
- Full study (free access) : Exposure to Diethylstilbestrol during Sensitive Life Stages: A legacy of heritable health effects, Birth Defects Res C Embryo Today, NCBI PubMed PMC3817964, 2013 Nov 5.
- Mechanisms involved in breast cancer etiology featured image credit PMC3817964/figure/F2.