[1] Wistar Inst Anat & Biol, Philadelphia, PA 19104 USA
[2] Danish Canc Soc, Inst Canc Biol, DK-2100 Copenhagen, Denmark
[3] Danish Canc Soc, Ctr Genotox Stress Res, DK-2100 Copenhagen, Denmark
[4] Univ Athens, Sch Med, Dept Histol & Embryol, GR-11527 Athens, Greece
[5] Demokritos Natl Ctr Sci Res, Inst Biol, GR-15310 Athens, Greece
[6] Stockholm Univ, Dept Genet Microbiol & Toxicol, S-10691 Stockholm, Sweden
[7] Univ Ioannina, Sch Med, Dept Physiol, GR-45110 Ioannina, Greece
[8] Natl Hellen Res Fdn, Inst Biol Res & Biotechnol, GR-11635 Athens, Greece
[9] Univ Penn, Dept Med, Div Gastroenterol, Philadelphia, PA 19104 USA
[10] Univ Copenhagen Hosp, Dept Pathol, DK-2100 Copenhagen, Denmark
[11] Aarhus Univ Hosp, Dept Clin Biochem, DK-8200 Aarhus N, Denmark
[12] Univ Sheffield, Inst Canc Studies, Sheffield S10 2RX, S Yorkshire, England
[13] Univ Geneva, Dept Mol Biol, CH-1211 Geneva 4, Switzerland