Chromosomal aberrations and risk of cancer in humans: an epidemiologic perspective

The pioneering papers published more than one century ago by Theodor Boveri opened the way to extensive research on the mechanism linking chromosomal abnormalities to the pathogenesis of cancer. As a result of this effort, robust theoretical and empirical evidence correlating cytogenetic damage to early stages of cancer in humans was consolidated, and an increased cancer risk was postulated in healthy subjects with high levels of chromosomal aberrations (CA). The first epidemiological investigation aimed at validating CA as predictor of cancer risk was carried out in the early 1990s. In that report the Nordic Study Group described an 80% increased risk of cancer in healthy subjects with high frequencies of CA. The results of this first study were replicated a few years later in a parallel research initiative carried out in Italy, and the subsequent pooled analysis of these two cohorts published in 1998 contributed to refine the quantitative estimate of the CA/cancer association. A small case-control study nested in a cohort of subjects screened for CA in Taiwan found an increased risk in subjects with high frequency of chromosome-type CA, while in 2001 a significant increase of cancer incidence associated with high levels of CA was described in a new independent cohort of radon exposed workers from the Czech Republic. Despite some common limitations affecting study design, the studies cited above have provided results of great interest both for the understanding of mechanisms of early stages of carcinogenesis, and for their potential implication for cancer prevention. The recent evolution of molecular techniques and the refinement of high throughput techniques have the potential to improve the knowledge about the role of specific sub-types of CA and to provide further insight into the mechanisms. Finally, the most challenging perspective in the field is the passage from research to regulation, with the implementatlon of preventive policies based on the accumulated knowledge