IL6 and carcinoma: RT-PCR analysis revealed a distinct, i.e., clone-specific, pattern of basal and stimulated expression of IL-6 mRNA in human colon carcinoma cells (Figure 1): As had been observed previously, carcinoma cell clones derived from well to moderately differentiated cancers, i.e. Caco-2 and COGA-1A, expressed only small amounts of IL-6, as compared with COGA-13 cells, which are derived from a poorly differentiated tumour.