Abstract: A method of diagnosing cancer by identifying differential modulation of each gene (relative to the expression of the same genes in a normal population) in a combination of genes selected from two groups of genes. Gene expression portfolios and kits for employing the method are further aspects of the invention.

Abstract: A method of extracting RNA from biological systems (cells, cell fragments, organelles, tissues, organs, or organisms) is presented in which a solution containing RNA is contacted with a substrate to which RNA can bind. RNA is withdrawn from the substrate by applying negative pressure. No centrifugation step exceeds thirty seconds. Preferably, the RNA is diluted prior to filtration and one or more wash steps can be used to remove interferents. In one such method, except for DNA shearing and drying steps, centrifugation is not undertaken during the extraction step.