Association of Elevated Serum Tryptase with Cutaneous Photodamage and Skin Cancers.

INTRODUCTION: Mast cells and their major protein, the serine proteinase tryptase, can be involved in cutaneous photodamage and carcinogenesis. The serum test of tryptase (S-tryptase) measures total tryptase protein (active tryptase and inactive protryptases), and S-tryptase is elevated in a variety of diseases, for example, in mastocytosis and α-tryptasemia. OBJECTIVES: The objective of this study is to study whether S-tryptase is a marker of cutaneous photodamage and carcinogenesis. METHODS: Adult subjects (n = 399, aged 21-79) evaluated to be at risk for skin cancers were recruited at the dermatological policlinic and examined for photodamage severity, mole count, actinic keratoses (AKs), skin cancers, and immunosuppression (IS). A blood sample was analyzed for S-tryptase using the ImmunoCAP® Tryptase fluoroenzymeimmunoassay. RESULTS: There was no difference in S-tryptase between non-IS (n = 321) and IS (n = 78) subjects or between genders. S-tryptase correlated slightly to photodamage and AKs in 321 non-IS subjects, and this association can be related, in part, to the age of subjects. In 34 subjects, S-tryptase was elevated (≥13.5 ng/mL), and in 20 males, but not in 14 females, the photodamage level was significantly (p = 0.031) more severe than in 179 males with normal S-tryptase. In contrast, there were more frequently subjects (n = 12) with past or present skin cancer (basal or squamous cell carcinoma or melanoma) in 14 females with elevated S-tryptase than in 186 female controls. So far, no explanation has been found for the elevated S-tryptase. CONCLUSION: There are significant associations between elevated S-tryptase and skin carcinogenesis, but the molecular mechanisms are unclear and gender differences can exist.