Relation between occupational exposure to organic solvents and chromosome aberrations in non-Hodgkin's lymphoma

Chromosome analysis of lymphoma cells was performed in 54 untreated patients with non-Hodgkin's lymphoma (NHL). 10 patients had a history of daily occupational handling of organic solvents for at least 1 year (exposed group) and 44 patients had never (or only for shorter periods) worked with solvents (unexposed group). There were no differences between exposed and unexposed patients regarding age, clinical stage or histologic malignancy grade. The patients were assigned to three categories: Patients with 0-4, 5-9, or greater than or equal to 10 cytogenetic events producing clonal aberrations of the lymphoma cells. The proportions of exposed patients in these categories were 2/26 (8%), 5/20 (25%) and 3/8 (38%); respectively, i.e. with increasing numbers of events there was an increasing probability of previous exposure to solvents (p = 0.035, trend analysis). 5 of 7 exposed patients (71%) with intermediate or high-grade lymphomas displayed translocations involving the band 14q32. Such 14q+ markers were found in only 5 out of 28 unexposed patients (18%) with lymphomas of comparable malignancy grade (p = 0.01). Among unexposed patients with intermediate or high-grade lymphoma the most common clonal aberration was 6q- which occurred in 10 out of 28 patients (36%). This abnormality was not observed in the exposed patients with lymphomas of corresponding malignancy grades (p = 0.08). It thus appears that the number of clonal chromosome aberrations is especially large in NHL patients with a history of occupational exposure to organic solvents. Moreover, such exposure may be associated with characteristic cytogenetic changes in the lymphoma cells.