Activity of O-6-methylguanine DNA methyltransferase in mononuclear blood cells of formaldehyde-exposed medical students

A recent study reported that exposure of student embalmers in Cincinnati to high concentrations of formaldehyde (2 mg/m(3)) reduced the activity of th e DNA repair protein O-6-methylguanine DNA methyltransferase (MGMT). Reduct ion in a DNA repair enzyme may strongly increase the cancer risk not only w ith respect to the repair-enzyme causing agent but with respect to all carc inogens causing lesions subject to repair by the enzyme in question. Thus, we examined whether formaldehyde exposure of 57 medical students during the ir anatomy course at two different Universities in Germany influenced MGMT activity in mononuclear blood cells. Mean formaldehyde exposure of 41 stude nts was 0.2 +/- 0.05 mg/m(3) for 6 h per week. MGMT activity was 133.2 +/- 14.9 fmol MGMT/10(6) cells before the beginning of the formaldehyde exposur e, 131.1 +/- 15.8 fmol MGMT/106 cells after 50 days (P = 0.56) and 128.2 +/ - 19.0 fmol MGMT/10(6) cells after 111 days of; exposure (P = 0.92). Simila rly, no significant influence of; formaldehyde exposure was observed, when smoking habits, alcohol consumption, allergic disease and sex of students w ere considered. In addition no significant difference was obtained in MGMT activity between 16 students with mean formaldehyde exposure of 0.8 +/- 0.6 mg/m(3) and students without formaldehyde exposure (n = 51; P = 0.37). In conclusion, exposure of the medical students in western Europe to formaldeh yde did not decrease MGMT activity in mononuclear blood cells.