The Cancer Cell, Its Entropy, and High-Dimensional Molecular Data

Cancer is a genetic disease, often caused by abnormalities in the genetic material of cancer cells. DNA copy number aberrations are an example of such abnormalities. The progressive accumulation, or entropy increase, of DNA copy number aberrations is the most consistent feature of the progression of tumors. For this surge in the number of DNA copy number aberrations to have any phenotypic (oncogenetic) effect, it needs to propagate to the transcriptomic level and beyond. This chapter investigates whether the genomic entropy increase is disseminated to the transciptomic level. To answer this question, first a statistical argument is provided, which suggests an affirmative outcome. This is confirmed more empirically by analyses of publicly available high-throughput data, for which tailor-made statistical methodology (dealing with the high dimensionality of the data) is developed. Two examples then illustrate that the genomic and transcriptomic entropy increase with cancer progression may be more than just an interesting observation in itself.