data-mining gene-expression kullback-leibler-divergence dimensionality-reduction pharmacogenomics principal-component-analysis breast-cancer targeted-sequencing relative-entropy alzheimers-disease-detection parkinsons-disease-detection finger-prick-blood at-home-testing disease-biomarkers receiver-operating-characteristic-curve differential-distributions toxicology-analysis multivariate-exploratory-data-analysis transcriptomics-markers neurodegeneration-detection