Benzene Exposure and Its Relation to Multiple Myeloma
JOSHI SC, PANT I, SHUKLA AN
Advanced medical and dental institute, Universiti Sains Malaysia, 29, Lorong Bertam Indah 4-9, Taman Bertam Indah, 13200 Kepala Batas, Pulau Pinang, Malaysia.
Dr. Sanjeev Chandra Joshi. Lecturer and Consultant in Oncology, Advanced medical and dental institute, Universiti Sains Malaysia, 29, Lorong Bertam Indah 4-9, Taman Bertam Indah, 13200 Kepala Batas, Pulau Pinang, Malaysia. Tel.: +6 045741887 (ext-115); e-mails: firstname.lastname@example.org, email@example.com
The positive epidemiological evidence for benzene as a risk factor for multiple myeloma is supported by biological plausibility. According to the investigators, findings are consistent with previous reports 9of haematological malignancies following occupational exposure to benzene and definitely raise the possibility that multiple myeloma could also be linked to benzene exposure. This does not necessarily mean that any increase in the incidence of multiple myeloma in recent years can necessarily be ascribed to benzene exposure, but it raises the issue that needs to be further investigated for relation between benzene exposure and multiple myeloma.
cite this article :
JOSHI SC, PANT I, SHUKLA AN. BENZENE EXPOSURE AND ITS RELATION TO MULTIPLE MYELOMA. Journal of Clinical and Diagnostic Research [serial online] 2007 August [cited: 2013 May 23 ]; 1:325-329. Available from http://www.jcdr.net/back_issues.asp?issn=0973-709x&year=2007&month=August&volume=1&issue=4&page=325-329&id=93
Introduction Human exposure to benzene in work environment is a global occupational health problem. Benzene is an established human carcinogen that may cause aplastic anaemia, acute myeloid leukaemia, myelodysplastic syndrome and multiple myeloma, among the workers who are occupationally exposed to benzene. Epidemiologic studies have suggested that benzene exposure may be a risk factor of multiple myeloma (1),(2). Here we are reviewing the literature for risk of multiple myeloma due to occupational exposure of benzene.
Review of Literature Benzene, an aromatic hydrocarbon, is used as a solvent for rubber, gum, resins, fats, and alkaloids, and in the manufacturing of drugs, dyes, and explosives. It has been used in manyindustries, including the manufacturing of artificial leather, natural leather products, enamels, rubber, waterproof fabrics, lacquers, shellac, paint removers, batteries, and bronzing, silvering and gilding liquids, in electroplating, lithography, photography, dry cleaning and feather preparation, and in the aeroplane, linoleum and celluloid industries (3). Certain petroleum fractions contain significant quantities of benzene and are often used to clean machinery parts or to remove grease from the hands. A benzene derivative is present in the exhaust gases encountered in the sulphite pulp industry (4). Benzene is volatile and, consequently, is readily absorbed by inhalation in badly ventilated rooms. It is also absorbed through the skin (5). In 1977, the National Institute for Occupational Safety and Health recommended that exposure to the workers should be less than 1 ppm (6). In industrialised countries, similar exposure limits have been established, but higher levels are common in the manufacturing sector of developing nations (7),(8). Benzene is found in gasoline, automobile emissions, and cigarette smoke (9), and a concern of possible benzene exposure in the general population has been raised, as the result of surveys, using sensitive assays of urinary metabolites of benzene (10). Great variations are noted among the workers occupationally exposed to benzene and its related mortality. Even low levels of benzene exposure may be potentially dangerous (11).
Regarding multiple myeloma, it is a tumour of plasma cells (12). These are antibody-producing cells derived from B lymphocytes, which are located primarily in the bone marrow. For the most part, the tumours are diffusely present within bone marrow, although occasionally individual tumours are found in extramedullary sites also. Despite the diffuse presence of myeloma cells within the marrow, in almost all the cases, multiple myeloma begins with somatic mutation in a single cell. This is evident from a major diagnostic test for this disease, the presence of a monoclonal antibody demonstrable on serum protein electrophoresis. Analysis of this reveals that it is uniform in its chemical composition, an elegant example of the origin of aberrant proliferate cell. Definitive diagnosis of multiple myeloma depends on the presence of an increased number of plasma cell, sometimes with abnormal morphology, in the bone marrow. Occasionally, an individual with an abnormal serum protein electrophoresis is observed who does not have bone marrow or other clinical findings consistent with multiple myeloma. These individuals with “benign monoclonal gammopathy” will occasionally progress to classical multiple myeloma (13).
Benzene Metabolism and Toxicology After inhalation or absorption, benzene targets organs, viz. liver, kidney, lung, heart, brain, etc. It is metabolised mainly in the liver by cytochrom
The positive epidemiological evidence for benzene as a cause of multiple myeloma is supported by biological plausibility for such an effect from benzene exposure. Studies done so far are difficult to interpret in relation to benzene exposure and risk of multiple myeloma. Nonetheless, they provide some support for an association between refinery work and multiple myeloma. According to the investigators, findings are consistent with previous reports of haematological malignancies following occupational exposure to benzene, and it definitely raises the possibility that multiple myeloma could also be linked to benzene exposure. This does not necessarily mean that any increase in the incidence of multiple myeloma in recent years can necessarily be ascribed to benzene exposure, but it raises the issue that needs to be further investigated for relation between benzene exposure and multiple myeloma.
Revised recommendation for an occupational exposure standard for benzene. National Institute for occupational safety and Health, U.S.P.H., CDC, DHEW, U.S. Government Printing Office No. 757-009/8, 1977.