Yes and no. Unfortunately, eBay has become something of a customer service nightmare for most people, as is evidenced by the results of any search for contact eBay, call eBay, chat with eBay, or similar phrases. Articles, blog posts, and websites offering contact information all give different answers, and most of them are wrong.
It inhibits the action of aromatase enzymes, which causes the body to produce less estrogen. Because many breast cancers are sensitive to estrogen, less estrogen in the body can help keep the cancer from spreading. Anastrozole is used for off-label reasons as well, such as treating excess estrogen production in men.
The role of estrogen in men is poorly understood by most non-specialists, and not fully understood by any as yet. Bodybuilders were the first adaptors of aromatase inhibitors in men, of course. Word quickly spread about the ability to use doses of the relatively inexpensive and potent testosterone esters beyond limits previously imposed by aromatase-driven, estrogenic side effects.