Two FDA-approved drugs may be as effective in treating cervical cancer in human cells as they are in mice, say researchers at the University of Wisconsin-Madison School of Medicine and Public Health.

Using mice genetically engineered to carry human papillomavirus (HPV) 16, known to be strongly associated with cervical cancer, Sang-Hyuk Chung, a postdoctoral fellow in lead author Paul Lambert’s lab, focused the study on the estrogen receptor (ER) alpha, which he discovered plays a key role in slowing the cancerous process.

Fulvestrant, an ER alpha blocker used to treat breast cancer, was the first drug tested on the HPV-positive mice with cervical cancer. After 1 month, Chung found that 11 of 13 mice lost all signs of cancer, but cancer remained in all the control mice that had not received the drug. The second drug tested, raloxifen, which is indicated for the treatment of breast cancer and osteoporosis, resulted in same strong receptor blocking effect as observed when fulvestrant was used. Researchers also gave the drugs to mice with precancerous lesions and found that ER alpha blockers prevented the lesions from progressing to cancer.

Lambert’s team is testing human cervical cancer cell lines to see if ER alpha blockers stop the growth of the malignant cells. The next step will be to test the drugs on tissue samples removed from women following cervical cancer surgery.

“We can’t be sure how the science will translate from animals to humans,” said Lambert, “but we have faith in our mouse model. There are many similarities in how cervical cancer develops and manifests itself in women and in mice.”

The study was published in Proceedings of the National Academy of Sciences (2009;106[46]:19467-19472).