Deceased numbers of spindle and cytoplasmic microtubules in hamster embryo cells treated with a carcinogen, diethylstilbestrol.

Diethylstilbestrol (DES) has been shown to induce neoplastic transformation in the absence of measurable mutations at specific loci in Syrian hamster embryo cells. It has been proposed that DES induces cell transformation via the production of aneuploidy. In the present study we document that concentrations of DES that cause aneuploidy also produce abnormal or arrested mitotic spindles. Thus, DES may disrupt spindle microtubules and produce aneuploidy that results in disordered gene expression and eventual neoplastic transformation.