Cytokine profiles in spontaneously regressing basal cell carcinomas

Background: Basal cell carcinomas (BCCs) can cause considerable morbidity due to their ability to enlarge progressively and to destroy underlying tissues. However, some Bccs may undergo spontaneous regression in the absence of therapy capable of inducing antineoplastic effects. Histological criteria for this process have been described, and previous studies have suggested that it may be mediated by infiltrating activated CD4- positive T cells. Objectives: The purpose of this study was to compare the expression of cytokines in actively regressing and non-regressing BCCs, to ascertain if active regression is associated with a particular cytokine profile. Methods: Reverse transcriptase-polymerase chain reaction, a sensitive, quantitative technique allowing analysis of multiple cytokines from small tumour samples, was used. Results Interferon (IFN)-γ was significantly elevated in actively regressing BCCs compared with non- regressing BCCs. Furthermore, interleukin (IL)-2, tumour necrosis factor (TNF)-β and CD3δ tended to be elevated in actively regressing tumours, although not to statistically significant levels. IFN-γ, IL-2, IL-10, TNF- β, granulocyte-macrophage colony-stimulating factor and Fas ligand showed strong positive correlations with CD3δ, indicating an association between infiltrating T cells and these cytokines. Conclusions: These findings support a role for T-helper 1 type cytokines in mediating spontaneous regression of BCCs.