Proposed Stem-like Characteristics Corresponding Assays Tumour initiation/ maintenance of tumour growth •In vivo transplantation The capacity for both symmetrical division (self renewal) and assymmetrical division (differentiation) It is impossible to assay for both attributes in a single cell/assay. Self renewal can be assayed for: •in vitro by the tumour sphere assay [48] •in vivo by serial transplantation Resistance to Anoikis (the form of apoptosis induced by cellular detachment) •In vitro Tumour sphere assay [48] •In vivo analysis of circulating tumour cells Metastasis formation (Combination of anoikis resistance and tumour initiation) •in vivo metastasis models e.g. by tail vein or intra-cardiac injection Drug resistance •In vitro/in vivo Cell survival following drug treatment

Table 1: Stem-like characterisitics associated with tumour cells and the corresponding assays used to test for them.