Meeting report of the EC/US workshop on genetic risk assessment: "human genetic risks from exposure to chemicals, focusing on the feasibility of a parallelogram approach".

This workshop was the concept of Professor Frits Sobels who passed away on the 6th of July 1993. The underlying idea of the Sobels' parallelogram approach is that an estimate (corrected by DNA-adduct dosimetry) of the genetic damage in human germ cells can be obtained by measuring a common endpoint in human and mouse somatic cells (such as gene mutation in lymphocytes) and in germ cells of mice, the desired target tissue inaccessible in humans. The main objective of the workshop was to identify the methodology, data requirements and mechanistic research to understand the human health impact of germ-cell mutagens. 4 chemicals were selected for review at the meeting: ethylene oxide, 1,3-butadiene, acrylamide and cyclophosphamide. The first 3 are important industrial chemicals with substantial use worldwide and, therefore, considerable potential human exposure. The 4th, cyclophosphamide, is a commonly used cancer chemotherapeutic agent. This first EC/US workshop on risk assessment was highly focused on the feasibility of the parallelogram concept to estimate potential germ-cell effects in humans. It represented an evaluation of current knowledge and the identification of future research needs for a more precise assessment of human genetic risks from exposure to mutagenic chemicals.