e13557 Background: The tetracyclic triterpene alcohol euphol is the main constituent found in the sap of Euphorbia tirucalli. In Brazil its latex is used as anticancer and other diseaseas folk treatment, yet, little is known about its anticancer proprieties. We aimed to study the antitumor effect of euphol on a large panel of human cancer cell lines. Methods: Anti-tumor effects of euphol in vitro were assessed using MTS assays on 77 human cancer lines from13 solid tumor models, such as breast, colon, bladder, prostate, lung, pancreas, esophagus, glioblastoma, melanoma, head and neck and cervical cancer. Additionally, we evaluate the its potential combinatorial value with temozolomide in gliomas. Ongoing experiments will identify potential drug target(s) by assessing changes in global protein expression. Results: Euphol exhibited dose and time-dependent cytotoxic effects on all cancer cell lines analyzed. Among each tumor type, the distinct cell line exhibited a heterogeneous profile of response to euphol. Esophageal squamous cell carcinoma and pancreatic carcinomas showed the most sensitive profile. In comparison with temozolomide, euphol showed a median of 30 fold higher efficacy, range 5-167 fold, in the glioma cell lines analyzed (Table). Conclusions: Euphol demonstrated potent anti-tumor activity on the majority of cancer cell lines evaluated. Our findings may provide insight into the tailoring designing of euphol-based therapies for cancer patients. [Table: see text]