As far as we know, this phenomenon has never been described in primary cell lines although other groups have shown similar phenotypes in tumor-derived cell lines including renal carcinoma38, choriocarcinoma20 and melanoma39, in which reduced IL-6 expression slows their proliferation, whereas blocking IL-6 or gp-130 using specific antibodies do not affect cellular growth. This evidence concerns the gene IL6 and neoplasm.