Fractal values of metal micro-aggregates in lung microenvironment associated with tumor complexity

Abstract

Quantitative analysis, using scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDAX), of inorganic particulate found in lung tissue has been carried out for different lung pathologies. Results show a marked correlation between adenocarcinoma and carcinoma in presence of heavy metals. Such association was not found on specimens related to before the massive Italian industrialization of the 1960’s. Most of the particles analyzed proved to be part of a coarse mode distribution. When their shapes were fibrous, they may be explained with fractal dimension. The aggregation processes have been simulated by a Diffusion-Limited Cluster Aggregation (DLCA) model. Results show that the significant part of the particulate matter was found in macrophages and has a fractal dimension that derives from a process of local aggregation of smaller particles rather than due to inhalation of larger coarse particles. Disruption of macrophage and tissue architecture due to aggregate deposition is significantly associated with lung cancer incidence.