Background. The incidence of malignant melanoma is increasing rapidly. The risk for development of malignant melanoma has been reported to be higher in persons of higher socioeconomic status. Methods. This case‐control study explores the relation between occupation and malignant melanoma relative risk through analysis of data collected by the American Cancer Society. A total of 1.2 million people were enrolled in a study of lifestyles and environmental factors in relation to mortality from cancer and other diseases. A total of 2780 persons had a history of malignant melanoma when the study began or developed malignant melanoma during the 6‐year study follow‐up period. The controls were matched for age, sex, race, and geographic location on an approximately 1:3 basis to persons selected from the remaining people enrolled. Results. In men, malignant melanoma risk was significantly higher in high‐paying versus low‐paying occupations (odds ratio [OR], = 1.58; P < 0.001) and in white‐collar versus blue‐collar occupations (OR = 1.33; P < 0.001). No significant conclusions could be drawn for women. No significant difference in risk was noted between those with indoor versus outdoor occupations. Among specific occupational exposures, only exposure to X‐rays significantly raised malignant melanoma risk (OR = 1.37; P = 0.002). Conclusion. Upper pay scale and white‐collar occupations significantly increase the risk for development of malignant melanoma. Cancer 1995;75:637‐44.

A method providing more sensitive detection of transglutaminase substrates was developed to localize transglutaminase activity in tissue and to identify in vivo substrates in epidermal extracts. The enhanced sensitivity of this method was achieved via the generation of a monoclonal antibody (designated E7) made to dansylcadaverine. Transglutaminase substrates were visualized by western blot after a 1-min incubation with dansylcadaverine in contrast to the 2 h required when [14C]putrescine incorporation was measured by autoradiography of SDS-polyacrylamide gels. In addition, putative substrates not apparent using conventional methods were readily detected by western analysis. An ELISA assay to measure transglutaminase activity showed similar sensitivity to the traditional radiometric assay (Lorand et al., 1972). The correlation between the ELISA procedure and the radiometric assay was high (r2 = 0.924). Strips of neonatal human and mouse skin incubated in dansylcadaverine-supplemented culture medium were used to localize enzyme activity and to detect substrates in vivo. Transglutaminase activity was demonstrated at the cellular periphery in the upper spinous and granular cell layers of the epidermis. Substrates detected in epidermal extracts were similar to those detected using the in vitro assay. This technique allows for highly sensitive and nonradiometric analysis of both enzymatic activity and the substrates involved. The extension of this methodology to an in vivo system is the first demonstration of a system in which the dynamics of cornified envelope assembly may be further studied.

Conclusive evidence for the carcinogenicity of tar used in dermatologic practice is lacking. Further controlled studies are necessary.