Objective: Microtubule stabilization has been shown to be the pathway by which Taxol induces apoptosis. We undertook in vitro experiments to evaluate the effects of Taxol on the cytoskeleton of different ovarian cancer cells.Materials and Methods: One human ovarian cancer cell line (420) and the solid component from two recently isolated epithelial ovarian tumors (HS-1, HS-2) were cultured adherently. The cells were exposed to Taxol (2 μM) for 4 hours. Forty-eight hours later, the cells were evaluated for differences in the cytoskeleton by immunostaining for tubulin and actin. Multimininucleation, which is consistent with apoptotic nuclei, was identified using Hoerscht DNA staining.Results: All the cells exhibited an organized cytoskeleton when stained for actin. The control 420 cells had an extensive fibrillar tubulin organization around the nucleus which did not change in appearance after treatment with Taxol, despite the multimininucleation which occurred. In constrast, the control HS-1 cells had diffuse, punctate tubulin which then accumulated in bundles at the sites of frequent mininuclei after treatment with Taxol. The HS-2 cells, after treatment with Taxol, accumulated tubulin around the periphery of the nucleus. However, there was no evidence of multimininucleation.Conclusions: The effect of Taxol on tubulin varies between ovarian cancer cell populations, but is homogenous within a cell population. There also appears to be a dissociation between tubulin response to Taxol and multimininucleation, as evidenced in the evaluated cell lines. Therefore, there may be a different mechanism of action for Taxol other than through microtubule stabilization. Whether these different tubulin responses to Taxol correlate with resistance merits further investigation.