Description: IC50 Value: N/A Docetaxel, an analog of taxol, is an inhibitor of depolymerisation of microtubules through binding to stabilized microtubules. Docetaxel is a clinically well-established anti-mitotic chemotherapy medication. It is used mainly for the treatment of breast, ovarian, prostate, and non-small cell lung cancer. in vitro: IC50 concentrations (reducing survival by 50%) ranged from 0.13-3.3 ng/ml, with three neuroblastoma lines proving most sensitive and three breast and two colon carcinoma lines showing least sensitivity [1]. Docetaxel was shown to promote the assembly of microtubule protein without GTP in vitro, but no inhibitory effect on DNA, RNA and protein synthesis [2]. Gene expression changes induced by paclitaxel treatment were mainly enriched in actin cytoskeleton (ACTC1, MYL2 and MYH2), tyrosine-protein kinases (ERRB4, KIT and TIE1) and focal adhesion pathway (MYL2, IGF1 and FLT1), while the expression alterations responding to docetaxel were highly co-related to cell surface receptor linked signal transduction (SHH, DRD5 and ADM2), cytokine-cytokine receptor interaction (IL1A and IL6) and cell cycleregulation (CCNB1, CCNE2 and PCNA) [4]. in vivo: The patients, between 15 and 80 years old with performance status (PS) of 0-2, received at least two cycles of docetaxel 60 mg m-2 intravenously at 3-4 week intervals [3]. Intestinal damage after repeated dosing of docetaxel (20 mg/kg) for 3 weeks was more severe at 14HALO than at 2HALO (hours after light on). The intestinal protein expressions of Wee1, phosphorylated CDK1, and cleaved Caspase-3 were higher in the 14HALO group than in the 2HALO group, while that of survivin was lower in the 14HALO group [5]. Toxicity: Twenty-five patients were enrolled. Overall, 13/25 (52 %, 95 % CI 34-70) completed 4 cycles, and 19/25 (76 %, 95 % CI 60-87) completed ≥3 cycles. Twenty of 25 patients (80 %) experienced a Grade 3 or 4 adverse event [6]. Clinical trial: N/A