Cathelicidin is expressed in the microenvironment of human melanoma tissue. Expression of human cathelicidin in melanoma tumor-infiltrating immune cells. Immunohistochemistry was performed using rabbit-anti-LL-37 Ab and expression in melanoma tissue was visualized by diaminobenzidine substrate (indicated by arrows). Dotted line represents the basal membrane. Epidermal staining was weak as expected in noninflamed tissue. n = 4, one representative data from four patients is shown. Original magnification ×100. De, dermis; Epi, epidermis; HF, hair follicle; MM, melanoma.