Sebaceous carcinoma in solid organ transplant recipients: The elegant path from epidemiology to etiology

Sebaceous carcinoma (SC) is a rare skin cancer associated with rapid progression and relatively poor survival, particularly in solid organ transplant recipients (SOTRs). Immunosuppressive regimens place SOTRs at substantially increased risk of a variety of skin cancers; recent research has shown a 25-fold increase in SC in the SOTR population, especially among lung recipients, older males, those with longer time since transplant, and patients undergoing induction therapy with thymoglobulin. The potential etiologic mechanisms underlying SC are multifaceted and complex. Immunosuppression creates a microcosm through which to view causative factors for carcinogenesis which has implications in elucidating mechanistic etiologies for SC far beyond the SOTR population, since not all cancers are more common in immunosuppressed patients. Research integrating the role of oncogenic viruses, underlying medical conditions, genetic risk factors, toxicity of prophylactic medications, drug-induced photosensitization, and T-cell deficiency/dysfunction is needed to better elucidate the factors underlying SC in immunosuppressed hosts. In this report, we integrate current research regarding SC in SOTR patients using the causal pie/sufficient-component cause model. In doing so, we provide a paradigm through which to view future research regarding the etiology of SC.