findings home/archives       contact us       other AHC publications   

June 2003 Issue

RSS feed

Cancer Research

Published June 2003

Sue Heffelfinger, MD, PhD, associate professor in the UC Department of Pathology and Laboratory Medicine, found that inhibiting angiogenesis (the growth of new blood vessels) in rats was as effective in preventing the development of breast cancer as was tamoxifen, an anti-estrogen treatment and preventive therapy used to prevent and slow breast cancer in humans. To Dr. Heffelfinger's knowledge, this is one of the first comparisons of angiogenic inhibitor and anti-estrogen drugs.

In earlier studies, a research team headed by Dr. Heffelfinger found that the number of tiny blood vessels in women's breasts increased as breast tissue progressed from normal to precancerous to full-blown cancer. Using a widely studied rat model of breast cancer, she was able to see that the ability of the rats' mammary tissue to induce new blood vessel growth actually preceded the first visible steps toward the development of breast cancer.

In this study, estrogen-receptor positive breast cancer was studied. Young female rats in the earliest stages of breast cancer were given a potent angiogenic inhibitor to prevent the growth of new blood vessels. The anti-angiogenesis treatment, called TNP-470, also inhibited the development of late pre-invasive and invasive breast cancer by 84 percent and 90 percent respectively. These decreases were as significant as those caused by tamoxifen.

Since the two treatments work through completely different mechanisms, TNP-470 slowing the growth of new blood vessels and tamoxifen slowing the estrogen to which the precancerous and cancerous tissues respond, the researchers reasoned that using both would have an additive effect, but found this to be incorrect. When used with TNP-470, tamoxifen performed less effectively than usual. The UC researchers believe this may be true because, by inhibiting new vessel growth, TNP-470 also inhibited delivery of tamoxifen to the tumor.

Dr. Heffelfinger suggests that combinations of agents be carefully studied in new studies involving animals, using various dosing and scheduling protocols, to determine maximum benefit.

 back to list | back to top