Cancer Biomarker Discovery: The Entropic Hallmark

Background: It is a commonly accepted belief that cancer cells modify their transcriptional state during the progression of the disease. We propose that the progression of cancer cells towards malignant phenotypes can be efficiently tracked using high-throughput technologies that follow the gradual changes observed in the gene expression profiles by employing Shannon's mathematical theory of communication. Methods based on Information Theory can then quantify the divergence of cancer cells' transcriptional profiles from those of normally appearing cells of the originating tissues. The relevance of the proposed methods can be evaluated using microarray datasets available in the public domain but the method is in principle applicable to other high-throughput methods. Methodology/Principal Findings: Using melanoma and prostate cancer datasets we illustrate how it is possible to employ Shannon Entropy and the Jensen-Shannon divergence to trace the transcriptional changes progression of the disease. We establish how the variations of these two measures correlate with established biomarkers of cancer progression. The Information Theory measures allow us to identify novel biomarkers for both progressive and relatively more sudden transcriptional changes leading to malignant phenotypes. At the same time, the methodology was able to validate a large number of genes and processes that seem to be implicated in the progression of melanoma and prostate cancer. Conclusions/Significance: We thus present a quantitative guiding rule, a new unifying hallmark of cancer: the cancer cell's transcriptome changes lead to measurable observed transitions of Normalized Shannon Entropy values (as measured by high-throughput technologies). At the same time, tumor cells increment their divergence from the normal tissue profile increasing their disorder via creation of states that we might not directly measure. This unifying hallmark allows, via the the Jensen-Shannon divergence, to identify the arrow of time of the processes from the gene expression profiles, and helps to map the phenotypical and molecular hallmarks of specific cancer subtypes. The deep mathematical basis of the approach allows us to suggest that this principle is, hopefully, of general applicability for other diseases

ICT, Financial Sector Development and Financial Access

This study assesses the role of ICT (internet and mobile phone penetration) in complementing financial sector development (financial formalization and informalization) for financial access. The empirical evidence is based on generalized method of moments with 53 African countries for the period 2004–2011. The following findings are established from linkages between ICT, financial sector development and financial activity. First, the interaction between ICT and financial formalization (informalization) decreases (increases) financial activity. Second, with regard to net effects, the expected signs are established for the most part. In spite of the negative marginal effects from financial informalization, the overall net effects are positive. Third, the potentially appealing interaction between ICT and informalization produces positive thresholds that are within ranges. Policy implications are discussed in three main strands. They include implications for (i) mobile/internet banking, (ii) a quiet life and (iii) ICT in reducing information asymmetry and surplus liquidity

Fighting Capital Flight in Africa: Evidence from Bundling and Unbundling Governance

This study investigates the effect of governance on capital flight by bundling and unbundling governance. The empirical evidence is based on 37 African countries for the period 1996–2010 and the Generalised Method of Moments. Governance is bundled by principal component analysis, namely: (i) political governance from political stability and ‘voice and accountability’; (ii) economic governance from government effectiveness and regulation quality and (iii) institutional governance from corruption-control and the rule of law. The following findings are established. (i) Political stability and ‘voice and accountability’ reduce capital flight while the collective effect of political governance is not significant. (ii) Economic governance increases capital flight whereas the individual effects of regulation quality and government effectiveness are not significant. (iii) Corruption-control and institutional governance negatively affect capital flight whereas the impact of the rule of law is not significant. (iv) Taken together, Corruption-control is the most effective governance weapon in the fight against capital flight. (v) Priority in the Washington Consensus is more effective at fighting capital flight compared to the Beijing Model. Policy implications are discussed

Political Regimes and Stock Market Performance in Africa

This paper assesses the effect of political institutions on stock market performance in 14 African countries for which stock market data is available for the period 1990-2010. The estimation technique used is a Two-Stage-Least Squares Instrumental Variable methodology. Political regime channels of democracy, polity and autocracy are instrumented with legal-origins, religious-legacies, income-levels and press-freedom qualities to account for stock market performance dynamics of capitalization, value traded, turnover and number of listed companies. The findings show that countries with democratic regimes enjoy higher levels of financial market development compared to their counterparts with autocratic inclinations. As a policy implication, the role of sound political institutions has important effects on both the degree of competition for public office and the quality of public offices that favour stock market development on the African continent