Paclitaxel is a compound extracted from the Pacific yew tree with antineoplastic activity. Paclitaxel binds to tubulin and inhibits the disassembly of microtubules, thereby resulting in the inhibition of cell division. Paclitaxel also induces apoptosis by binding to and blocking the function of the apoptosis inhibitor protein Bcl-2 (B-cell Leukemia 2). Paclitaxel inhibits DNA synthesis and stimulates the release of tumor necrosis factor-α. Paclitaxel induces apoptosis in murine mammary carcinoma MCA-4 and ovarian carcinoma OCA-1 tumors.