IL1B and neoplasm: Cocultivation with melanoma cells alone induced expression of the activation marker a‐SMA twofold (data not shown) but did not induce SAA1 RNA expression in fibroblasts compared to fibroblast monoculture (Figure 3b), probably due to the presence of serum‐derived factors also known to enhance SAA1 expression masking the stimulating effect of tumor cell–derived IL1β.