Anaplastic thyroid cancer (ATC) does not have a well-defined medical treatment, surgery is often not possible, and chemotherapy and radiotherapy are the main treatments. It has previously been shown that disease orientated in vitro screening using human tumour cell lines has some use in predicting clinical responses to treatment. Previously primary ATC cell cultures (ANA) have been developed from surgical biopsies, however the possibility of obtaining ANA from fine-needle aspiration (FNA-ANA) and testing sensitivity to different drugs could increase the effectiveness of treatments and avoid unnecessary surgery. The study used six patients before they had undergone surgery to obtain FNA-ANA samples by FNA cytology, which were cultured and propagated. Chemosensitivity was then evaluated by inhibiting cell proliferation with increasing concentrations of five chemotherapeutic agents (bleomycin, cisplatin, gemcitabine, ectoposide, and carboplatin) or thiazolidinediones (rosiglitazone). The FNA-ANA chemosensitivity was found to be similar to that of primary cells from each of the patients’ tumour biopsies. Chemotherapeutic agents significantly inhibited FNA-ANA proliferation, and ectoposide was found to be the most effective in reducing cell growth in vitro. The authors conclude that the possibility of testing chemosensitivity to different drugs in individual ATC patients is able to increase the efficacy of drug treatment and avoid the administration of ineffective drugs. Antonelli, A., Ferrari, SM., Fallahi, P., Berti, P., Materazzi, G., Marchetti, I., Ugolini, C., Basolo, F., Miccoli, P., and Ferrannini, E. European Journal of Endocrinology 2008 159: 283-291 DOI:10.1530/EJE-08-0190