CD34 and skin basal cell carcinoma: Considering that the distribution of CD34 antigen may have significance in understanding the organizational and growth pattern of BCC tumor masses, and in elucidation of the adaptive mechanisms of uninvolved skin to tumor tissue, the aim of this research was to analyze the immunohistochemical presence and morphological distribution of CD34 antigen in: (1) tumor masses (tumor nests and tumor stroma) of different types of BCC, (2) peritumoral skin (juxtatumoral and transitional zone), and (3) structures of marginal, morphologically normal skin in the biopsies.