Malignant pleural mesothelioma is a highly aggressive and therapy-resistant tumor with poor prognosis. Approximately 80% of MPM cases worldwide are associated with exposure to asbestos. Incidence of MPM has increased in the world. Most patients survive around 12 months in spite of given treatments. Since about 80% of MPM cases have been diagnosed in stage III/IV, they are no longer suitable for surgical intervention. Moreover, the conventional therapy strategies have failed to extend survival of MPM patients. Although the combination therapy, consisting of cisplatin and pemetrexed, has shown promising prognostic results and became the standard first-line treatment for mesothelioma, it has not yielded satisfactory outcomes regarding overall survival of patients. For these reasons, more effective therapy strategies are still needed. In this review, in vitro research studies that are related to inhibitors administrated on MPM cells are summarized. Results of in vitro studies are important for identification of potential therapeutic agents.