1. Introduction The word hyperthermia, as a term has its roots in the Greek word «Υπερθερμία», which means, the generation of heat in high level. The standard therapies for cancer treatment are based mainly on chemotherapy, radiotherapy and direct surgery. Sometimes a combination of these techniques is preferred [1]. In order for the cancer treatment to become more efficient, the oncologists use heat treatment in combination with the above methods. By performing heat treatment procedures, cancer cells are made more vulnerable to these therapies [2]. A complete and effective cancer therapy has to maximize the therapeutic efficiency while minimizing any side effects to the adjacent healthy tissues [3]. Hyperthermia treatment can force the cancer cells to be destroyed, by increasing the temperature of the cancerous tissue to 42ºC [4-6]. Hyperthermia can be considered a therapy because the increase of temperature locally within the tumor up to 42ºC destroys cancer cells, driving them to apoptosis [7]. Hyperthermia is also a viable method, when tumors have not metastasized and their regions are well known. Further, it is favorable when a tumor cannot be surgically removed [8]. Depending on the temperature, hyperthermia can be classified into two different types: 1) Moderate Hyperthermia, where the temperature within the tissues is in between 41–46ºC [9] and 2) Thermo- ablation, where the temperature within the tissues is from 46-50ºC, which yields widespread necrosis, coagulation or carbonization [10]. The efficiency of the hyperthermia treatment depends on the level of the temperature generated, the duration of exposed and the type of the cancer cells [11]. Magnetic hyperthermia is considered a powerful and promising technique which has the potential to be a practical cancer therapy [12]. This is because the side effects of such a therapy are very low, compared with other cancer treatments [13]. The treatment by using magnetic hyperthermia starts with the dispersion of magnetic nanoparticles (MNP’s) throughout the target Central European Journal of Chemistry In vitro magnetic hyperthermia response of iron oxide MNP’s incorporated in DA3, MCF-7 and HeLa cancer cell lines * E-mail: egkanas@uowm.gr Received 12 November 2012; Accepted 15 February 2013 Abstract: © Versita Sp. z o.o. Keywords: Magnetic nanoparticles • Magnetic hyperthermia • Cancer cell lines • Thermal decomposition Environmental Technology Laboratory, Institute of Nuclear Technology and Radiation Protection, NCSR “Demokritos”, Agia Paraskevi, Athens 15310, Greece Department of Materials Science and Engineering, University of Ioannina, Ioannina 45110, Greece Evangelos I. Gkanas * Research Article In the current work, iron oxide magnetic nanoparticles (MNP’s) were synthesized by thermal decomposition of Fe(acac) 3 -(iron acetylac- etonate) compounds in high-boiling organic solvents containing stabilizing surfactants and examined as possible agents for magnetic hyperthermia treatment, according to their structural, magnetic and heating properties. Three different cancer cell lines (DA3, MCF-7 and HeLa cell lines) were used to assess the suitability of the MNP’s. The experimental results proved that the synthesized MNPs are non–toxic and the uptake efficiency was extremely good. Further, from in vitro hyperthermia results, very fast thermal response was observed (reaching hyperthermia levels in less than 200 s), which minimize the duration of the cell and human body exposure in a high frequency AC external magnetic field. 1042 Cent. Eur. J. Chem. • 11(7) • 2013 • 1042-1054 DOI: 10.2478/s11532-013-0246-z