THE PRESENCE OF IMMUNOSUPPRESSIVE P15E-LIKE FACTORS IN THE SERUM AND URINE OF PATIENTS SUFFERING FROM MALIGN AND BENIGN BREAST-TUMORS

Certain types of tumours are capable of producing factors inhibiting m ononuclear phagocyte chemotaxis which may contribute to defects in imm unosurveillance. In head and neck cancer these factors are said to be related to the retroviral protein p15E. This study examines the presen ce of p15E-like factors in serum and urine of patients with malign and benign breast tumours. Thirty patients with breast cancer, 29 patient s with benign breast masses, and 28 healthy controls were tested blind ly with the monocyte polarization assay, using N-formyl-methionyl-leuc ylphenylalanine as chemoattractant. The low molecular weight fractions prepared of sera of the malign tumour patients inhibited the monocyte polarization significantly (mean inhibition 34%, s.d. = 12) compared with those of benign tumour patients (15%, s.d. = 7) and of controls ( 14%, s.d. = 6). The observed inhibitory effects on the monocyte polari zation could be compensated by MoAbs reactive to p15E-related antigens . The mean difference between the polarization inhibition with and wit hout anti-p15E adsorption (the 'p15E-like factor-induced inhibition') was 25% (s.d. = 13) in the breast cancer group, compared with 7% (s.d. = 5) in the benign tumour patients and 501. (s.d. = 4) in the healthy control group. Surgical removal of the tumours resulted in a restorat ion of the monocyte polarization in 20/23 (87%) patients of the breast cancer group. Results testing preoperative urine samples correlated w ell with those of corresponding sera. These data give additional suppo rt to the concept that tumour-derived p15E-like factors are responsibl e for the inhibitory effect on monocyte chemotaxis in breast cancer pa tients, and that these factors can be found in serum as well as in uri ne.