This finding concerned researchers since parabens have been shown to be able to mimic the action of the female hormone estrogen, which can drive the growth of human breast tumors.

However, this study showed no direct evidence that deodorants were linked to an increased risk of breast cancer. Further work is required to examine any association between estrogen and other chemicals found in deodorants and breast cancer, researchers say.

BBC News January 11, 2004

I have posted articles in the past warning of the dangers of antiperspirants, and now this study is raising concerns about deodorants as well. Antiperspirants and deodorants are not the same thing: Antiperspirants work by clogging, closing, or blocking the pores that release sweat--with the active ingredient being aluminum--so that they can’t release sweat. Deodorants work by neutralizing the smell of the sweat and by antiseptic action against bacteria, but do not prevent sweating.

The concern with antiperspirant is that the aluminum it contains is absorbed by the body and wreaks havoc in the brain, where it likely contributes to the growing numbers of people coming down with Alzheimer’s disease. So it appears that the urban legend that antiperspirants have been identified as the leading cause of breast cancer may actually have some truth to it.