IL4 and renal cell carcinoma: For example, IL-4 can mediate modest inhibition of proliferation of human renal cell carcinoma (Obiri et al, 1993), melanoma (Hoon et al, 1991), breast and colon carcinoma (Toi et al, 1992), and non-small cell lung carcinoma cell lines (Topp et al, 1993a, b).