'DES Daughters' Had Increased Rates Of Cancer; An Animal Study Shows 'DES Granddaughters' May Too

DES, or diethylstilbestrol, is the synthetic estrogen once used in attempts to treat women at risk for miscarriage.

Now, scientists at the National Institute of Environmental Health Sciences report that they have observed an increase in cancers, including cancer of the uterus, in female mice whose mothers were exposed to DES in utero -- while in the uterus. The subsequent generation of female mice reported today was not exposed to DES.

While both generations had increased reproductive tract cancers, fertility was impaired only in the female mice exposed to DES in utero (the 'DES daughters') but not in their unexposed female offspring (the 'DES granddaughters'), the scientists said.

The study was reported today in the scientific journal Carcinogenesis (September, pp. 1655-1663) by Retha R. Newbold, Rita B. Hanson and Wendy N. Jefferson, all of NIEHS; Bill C. Bullock of the Bowman-Gray School of Medicine at Wake Forest University, Winston-Salem, N.C.; Joseph Haseman of NIEHS, and John A. McLachlan of Tulane/Xavier Center for Bioenvironmental Research, Tulane University, New Orleans.

Newbold and her colleagues said "the data suggest transmission of susceptibility of genital tract cancers to subsequent generations." They said this concept is supported by results in male mouse siblings in which like the females described in this study, reproduction is not affected but rare cancers are observed. A report on the effects in males is being completed, Newbold said.

Newbold and her colleagues said that although additional study of risks from environmental agents are needed, the findings "indicate that the cascade of events that lead to the appearance of a tumor may well begin before birth and perhaps before conception."

For more than 20 years, beginning in the 1940s, DES was commonly prescribed to pregnant women to prevent miscarriages, but the practice was abandoned after 1971 when investigators found an extremely rare reproductive tract tumor, vaginal adenocarcinoma, in the young daughters of the treated women. Although the incidence of cancer was ultimately determined to be low, other abnormalities, including poor reproductive outcome in DES daughters, are quite common.

Other well-known uses of DES, such as to fatten cattle and chickens, have also been discontinued.

###

Carcinogenesis is available on the Web at http://www.oup.co.uk/carcin