Given that apoptosis is an active response by the cells, similar to other differentiation programmes, pathological context of apoptosis induction. One of the most important applications of the apoptosis genes presented in this work will be the annotation of genes that are differentially expressed by microarray analysis, which we exemplified in figure 6. Our functional data can in particular contribute to the massive sequencing efforts to distinguish those mutations underlying tumourigenesis in the “cancer genome” from those that are mere “passengers”. As it is the upregulation of the genes that activates them for apoptosis, we would expect that it complements microarray data, which record such transcriptional changes. This combination will add an important functional aspect to the correlative data produced by microarrays. A case in point is the determination of hemoglobin as an apoptosis inducer in our screen and in microarray analysis. While surprising, hemoglobin has been found in later LY2157299 studies to be upregulated in various cell types and responsible for apoptosis. After our first reports on the apoptosis screen and its technology similar screens for dominant apoptosis inducers were published by other groups. One approach isolated a number of genes that were described as potential tumour suppressor genes. Other researchers screened and identified three genes out of 938 hypothetical genes as apoptosis inducers using standard transfections in combination with subcellular imaging, western blotting, and DNA fragmentation ELISA. The most comprehensive effort so far to screen for cell deathinducing genes was performed by testing pools of genes each comprising 96 cDNAs from a T-cell library. This screen produced, besides factors that also induce alternative phenotypes of cell death, 64 genes for apoptosis induction. Interestingly, only three genes overlap with our gene collection possibly indicating differences between the libraries used. Other technical approaches have been employed to screen for apoptosis mediators. Reverse transfection cell array technology arrays the transfection mixes, each containing an individual gene of interest, onto glass slides, which are then overlaid with cells. With this approach a collection of 382 human sequenceverified, full-length open reading frames were screened for proapoptotic genes and seven genes were identified. A similar cell array screen was also performed with 1,959 mammalian open reading frames from the Mammalian Genome Collection with 10 proapoptotic genes eventually being verified. In summary, we believe that this study demonstrates that testing gene activities by individual transfections holds great promise to the definition of the functome of apoptosis and can have applications in other functional read-outs as well. Cancers that spread from their original site to another area of the body, are called metastatic cancers. metastatic cancers have poor prognosis and high mortality. A full understanding of the biological mechanism involved in metastasis and rational approaches to preventing or controlling metastasis can lead to practical approaches for improving survival rate of patients afflicted with metastatic cancers.