The activity of antibodies was determined in tests assessing the inhibition of the antiproliferative action of IFN-β on 3 human tumor lines: MCF7 (ATCC HTB-22) breast cancer carcinoma, HT-29 (ATCC HTB-38) colon carcinoma and AGS (ATCC CRL-1739) gastric carcinoma. Here, IFNB1 is linked to neoplasm.