In addition to destroying parasites, the benzimidazole drugs used as anthelmintics also inhibit microtubule polymerization and have been reported to exhibit antitumor effects. However, it is not yet clear whether these properties would be applicable to a human cancer.
The anecdotal claim that fenbendazole can cure cancer is based on the story of Joe Tippens, who says he was cured of his lung cancer by taking fenbendazole along with other conventional treatments, such as radiation and chemotherapy. However, it is impossible to reliably attribute his remission to fenbendazole alone because he never had a control group and was already receiving multiple other conventional therapies at the time he began taking fenbendazole.
Furthermore, several experiments have shown that fenbendazole does not alter tumor growth or radiation response in mice and human cell lines. These experiments, shown in the table below, compared the effect of three daily i.p. injections of fenbendazole on the growth and radiation response of EMT6 tumors in BALB/cRw mice. The growth of the tumors was measured from the time when it became palpable until it reached a volume of four-times its original size, and then the data were stratified by tumor-bearing mouse, and the time to reach that volume was calculated for each treatment group.
Inhibition of tubulin polymerization by fenbendazole does not affect cyclin B1 levels or the onset of mitosis in A549 cells, a human colon cancer cell line. During mitosis, the separation of chromosomes requires the assembly and maintenance of a structure called the mitotic spindle, which is composed of microtubules. Inhibition of the formation of these structures by fenbendazole does NOT prevent mitosis, but it may impair proper separation of chromosomes by preventing the binding of cyclin B1 to CDK1. fenbendazole cancer treatment