As gene therapy and other macromolecular medicines become more important in the treatment of cancer and other diseases, the need for more appropriate in vitro assays in which to test them also increases. At present, complex genetic treatments are often tested in vitro on monolayer cultures or single cell suspensions, which are vastly different in both physical and, sometimes, genetic characteristics from their in vivo situation. This means that many therapeutics have to be tested in animals or humans before problems with their delivery are discovered. This study aimed to characterise three dimensional (3-D) in vitro models of tumour cells and assess their usefulness at representing the in vivo situation more accurately in vitro.