UP-REGULATION OF A TUMOR-ASSOCIATED ANTIGEN (TAG-72) BY INTERFERON-ALPHA AND INTERFERON-GAMMA IN PATIENTS WITH CUTANEOUS BREAST-CANCER RECURRENCES

Up-regulation of a tumor-associated antigen (TAA) TAG-72 was investiga ted immunohistochemically in skin recurrences of 10 breast cancer pati ents treated with intralesional injections of natural interferons (nIF Ns) alpha and gamma. Up-regulation was assessed by comparing the immun oreactivity of pre-IFN and post-IFN specimens stained with monoclonal antibodies (MoAbs) B72.3 and CC49 at near end-point dilutions. Varying degrees of enhanced immunoreactivity were detected in IFN-injected an d non-IFN-injected lesions except in 1 patient with high constitutive expression of TAG-72 and another patient not expressing TAG-72. Thus, IFN-mediated up-regulation of TAG-72 can occur in patients whose breas t cancer cells express this TAA, independently of the initial levels o f antigenic expression.