TRANSFORMING GROWTH-FACTOR-BETA DISTRIBUTION IN BASAL-CELL CARCINOMAS- RELATIONSHIP TO PROLIFERATION INDEX

Transforming growth factor-beta (TGF-beta) distribution in basal cell carcinomas (BCCs) was studied using polyclonal antibodies recognizing intra- (precursor) and extracellular (activated) forms (LC 1-30 and CC 1-30), and compared with an index of cell proliferation (PCNA immunor eactivity). Intracellular TGF-beta is found in suprabasal keratinocyte s and the outer root sheath. Extracellular TGF-beta is largely absent from normal skin, but is abundant in the intercellular spaces of hyper plastic epidermis overlying BCCs. Twenty-five of 29 BCCs showed increa sed extracellular TGF-beta in the desmoplastic stroma, with intercellu lar staining in nine of these. Intracellular TGF-beta was present in f ibroblasts and endothelial cells, although only 17 of 29 BCCs were pos itive, predominantly in central cells showing apparent maturation. Lit tle correlation was seen between the degree of staining of tumour cell s and the distribution of extracellular TGF-beta. PCNA immunoreactivit y was greater in BCCs compared with normal epidermis in 24 of 37 cases (P=0.005), and was concentrated on the periphery of nodular BCCs. Str ongest stromal reactivity for TGF-beta and maximal PCNA index also sho wed a significant correlation (P=0.023). This study demonstrated abund ant TGF-beta in the active stroma around BCCs, which may account for m any of the morphological and functional characteristics of this tumour , but which may be a product of stromal rather than tumour cells.