Description

Increased of over 100% in age standardized incidence of cutaneous melanoma have been seen in Canada over the past 20 years. Increases of 50-60% have been seen for squamous and basal cell carcinoma of the skin. Although we have made major advances in elucidating the relationship of these cancers to solar U.V. light exposure, we do not yet know enough to undertake a primary prevention program.

If high risk individuals can be reliably identified, however appropriate medical advice and surveillance can be offered to select high risk group in order to minimize mortaility and morbidity from these three skin cancers. Unfortunately, epidemiologic risk factors known to discriminate between high risk subjects and subjects and subjects at low risk are neither very sensitive nor specific.

The aim of this study is to evaluate whether a new blood test designed to assess DNA damage repair capability in circulating lymphocytes will predict subjects who are at high risk for melanoma, squamous cell carcinoma and basal cell carcinoma.

Two hundred patients with melanoma, 200 with squamous cell and 200 with basal cell carcinoma of the skin will be recruited and data will be collected on epidemiologic risk factors which are currently the best predictors of skin cancer risk. These include a number of acquired melanocytic nevi, degree of freckling, skin reflectance, propensity to burn in the sun, degree of solar exposure and other factors. Four hundred matched controls will be recruited from the general population and identical data will be collected on each subject.

Each study subject will also be requested to donate a sample of blood. From the blood, lymphocytes will be isolated, and will be tested for their capacity to repair U.V. induced DNA damage using a chloramphenicol acetyltransferase plasmid reactivation assay (CAT-DRC assay). Values for the CAT-DRC assay alone will be compared to standard risk factors in discriminating melanoma, SCC or BCC patients from controls.

If the CAT-DRC test is useful in discriminating between skin cancer patients and controls it may be the step in the process of producing a practical blood test for predicting individual in the population who are at high risk for both melanoma and non-melanocytic skin cancer.

Principal Investigator

• Richard Gallagher