[Cancerogenic effect of long-term benzene exposure. Occurrence at the same work place of a plasmacytoma and two solid...

A report is given on three different malignomas appearing after high inhalative exposure to benzene for many years at the same working place in a cable plant. The exposure to benzene amounted to 22 years in a 50 year old man with oesophagus carcinoma, 17 years in a 61 year old man with plasmocytoma and 10 years in a 45 year old man with embryonal carcinoma of the testicles. The malignomas appeared 5-7 years after the end of the exposure. The carcinogenity of benzene is discussed on the basis of a survey of medical literature on epidemiological studies, casuistic contributions and experimental investigations in animals. A direct and indirect mechanism of benzene inducing carcinogenity is discussed: Activation of normal cellular oncogenes in DNA molecules by changes directly caused by benzene and; Damage of the lymphatic cell particularly susceptible to benzene followed by a disturbance of immunological monitoring and defence reactions against tumour cells.