The role of immunosuppression in the pathogenesis of basal cell carcinoma

Conflicts of interest: none declared. Sir, Tilli et al. in their comprehensive review of the molecular aetiology and pathogenesis of basal cell carcinoma (BCC) questioned the impact of a depressed immune system in the development of BCC.1 They alluded to the lack of evidence to support an increase in BCC incidence rates following organ transplantation and stated that ‘immunosuppression as practised after organ transplantation does not increase the risk of developing BCC’. The paucity of reliable evidence in relation to post‐transplant BCC is in part a reflection of the practice of most cancer registries, not to record BCCs, or instead to include both squamous cell carcinoma (SCC) and BCC under the collective heading of nonmelanoma skin cancer.2, 3 In addition, many registries will register only the first nonmelanoma skin cancer for an individual, a practice which would result in a significant underestimation of the skin cancer burden of a transplant population, where individuals often develop multiple skin cancers.4