BOSTON — At first, the Melnick sisters thought it was just a cruel coincidence that two of them got breast cancer.
But when two more sisters were given the same diagnosis, they came to suspect that a drug their mother took while pregnant in the 1950s had something to do with it.
The four women are suing a former maker of DES, or diethylstilbestrol, in a case set to unfold in federal court today, when it will become one of the first of scores of such claims nationally to go to trial. The Melnick women seek unspecified damages.
The numerous pharmaceutical companies that made or marketed the drug argue that no firm link has been established between breast cancer and DES, a synthetic estrogen prescribed to millions of women from the late 1930s to the early 1970s to prevent miscarriage, premature births and other problems.
It was eventually pulled from the market after being linked to a rare vaginal cancer in women whose mothers used DES. And studies showed the drug did not prevent miscarriages after all.
All four Melnick sisters had miscarriages, fertility problems or other reproductive tract problems long suspected of being caused by prenatal exposure to DES.
Then in 2008, one sister read about a study reporting an increased incidence of breast cancer in the daughters of women who took DES during pregnancy.
"That's when we really started to say, 'Wow, there really could be a link. It's not just in our head,' " said Donna Melnick McNeely of Las Cruces, N.M., who was diagnosed with breast cancer at 49.
The sisters say they have compelling anecdotal evidence within their family: Their mother took DES while pregnant with Donna, Michele, Andrea and Francine. All had reproductive problems and developed breast cancer in their 40s. But their mother did not take DES while pregnant with the oldest sister, Mary Ann, who had no fertility issues or breast cancer.
Eli Lilly and Co., the drug company being sued by the sisters, dominated the market for DES. The company argues in court documents there is no evidence the women's mother, Frances Melnick, took DES.