Arsenic and cancer: The still unanswered question

Abstract

For some 2500 yr, As was considered an important element of pharmacopeias and was praised for its medicinal qualities. An incidental link with cancer was suggested during the 19th century, and since that time a controversy has ensued with regard to the compound''s tumorigenicity. Several epidemiological surveys suggested that As induces lung, liver or skin cancer in humans. All experimental attempts to reproduce such neoplasms in laboratory animals consistently failed, thereby denying support to the human data. Recently As was reported to be mutagenic. Because of the inconsistency of most mutagenesis findings at present, this also cannot be regarded as supporting evidence. A recent trend was to consider As as beneficial in cancer prevention and in maintaining the health of farm animals and, perhaps, humans. A critical review of epidemiological and experimental data from the literature was made in an attempt to present an objective picture of this controversial and sensitive question and to encourage further research, which may ultimately determine whether arsenic deserves its execrable reputation.