Utilization of virtual samples to facilitate cancer identification for DNA microarray data in the early stages of an investigation

DNA microarray datasets are generally small in size, high dimensional with many non-discriminative genes, and non-linear with outliers. Their size/dimension ratio suggests that DNA microarray datasets are identified as small-sample problems. Recently, researchers have developed various gene selection algorithms to discover genes that are most relevant to a specific disease, and thus to reduce computation. Most gene selection algorithms improve learning performance and efficiency, but still suffer from the limitation of insufficient training samples in the datasets. Moreover, in the early stage of diagnosing a new disease, very limited data can be obtained. Therefore, the derived diagnostic model is usually unreliable to identify the new disease. Consequently, the diagnostic performance cannot always be robust, even with the gene selection algorithms. To solve the problem of very limited training dataset with non-linear data or outliers, we propose the method GVSG (Group Virtual Sample Generation), which is a non-linear Virtual Sample Generation algorithm. This non-linear method detects the characteristics in the very limited data, forms discrete groups of each discriminative gene, and systematically generates virtual samples for each of these to accelerate and stabilize the modeling process. The results show that this method significantly improves the learning accuracy in the early stage of DNA microarray data.