Skin Carcinogenesis: A Health Problem Meets with a Scientific Challenge Concluding Remarks and Future Prospects

Abstract

The symposium on which this book was based was intended to bring together clinicians and experimental scientists engaged in research in skin carcinogenesis. The field of skin carcinogenesis seems to be particularly well suited for such an approach, for two reasons:

• 1. Among the white population skin cancer is by far the most frequent form of malignant neoplasia and, as far as malignant melanoma is concerned, also a serious threat. Skin cancer was the first neoplastic disease shown to be caused by environmental factors. More than 200 years ago, Sir Percival Pott made the revolutionary suggestion of a causal relationship between skin cancer in chimney sweeps and chronic contact with soat and tar. About a century later, Unna discussed the possibility of skin cancer being related to sun exposure and in 1902 Frieben demonstrated the skin-carcinogenic potential of X-rays. Finally, the reader may be reminded of Guiffo’s results showing a transplantable or infectious agent to be involved in the generation of skin warts, which is considered to be a landmark in tumor virology. So, the three major types of exogenous factors accused of being involved in carcinogenesis were deteced using skin as a target organ (reviewed in Marks 1989).

• 2. After the famous coal tar experiment of Yamagiwa and Ichikawa (1914), animal skin became the classic and most widely used model for the detection of environmental carcinogens as well as for experimental purposes, and important concepts such as multistage carcinogenesis were developed for the first time by employing this model. These also include the biological characterization of key compounds of carcinogenesis such as the polycyclic aromatic hydrocarbons and the phorbol ester tumor promoters. Thus, experimental skin carcinogenesis quickly overcame the limits of dermatology, developing into an approach thought to provide general information on the induction and development of benign and malignant epithelial tumors.