Chapter 34 - Significance of QSAR in cancer risk assessment of polycyclic aromatic compounds (PACs)

Abstract

The quantitative structure–activity relationship (QSAR) model is highly relevant in estimating the cancer risk posed by human exposure to polycyclic aromatic compounds (PACs) laden in the environment. The application of QSAR helps to bridge existing knowledge gaps in the lack of available data on toxicity equivalency factors (TEFs) for some PACs, particularly polycyclic aromatic hydrocarbons (PAHs) and their associated transformed PAH products (TPPs), thereby minimizing the cost and time associated with the conduct of animal toxicological test. To produce a reliable TEF result that can be used to estimate the carcinogenic human health risks of PACs, four essential sequence of steps entailing data preparation, data processing, model development and validation, and data interpretation were used. Partial least squares regression QSAR modeling was found to be most suitable in predicting the TEFs based on statistical validation such as standard deviation of error of prediction and predicted residual sum of squares. The utilization of the QSAR generated TEFs and the initially existing TEFs for outlier PAHs and TPPs led to a more accurate and holistic estimation of the total incremental lifetime cancer risk posed by these hazardous pollutants to adults and children. However, there is the need to explore the relevance of QSAR application in estimating the health risk posed to living organisms by other categories of persistent organic compounds in the environment.