Prognostic value of concentration of pregnancy-specific beta 1-glycoprotein (SP1) in serum of patients with breast cancer.

Abstract

Pregnancy-specific beta 1-glycoprotein (SP1) was assayed by particle counting immunoassay in serum from 46 healthy female blood donors, 33 patients with benign mastopathy and 84 patients with breast cancer before operation and during follow-up. Values greater than 1 micrograms/1 were found more frequently with benign mastopathies (11/33) and in patients with breast cancer at stage 2 (20/48), 3 (4/9), and 4 (7/10) than in healthy female blood donors (3/46). The survival rate after 4 years was significantly lower in patients with SP1 level greater than 1 microgram/1 before tumor resection (52% vs. 87%). The difference remained significant when only patients in stage 2 were taken into account (57% vs. 85%). A highly significant (r = 0.64; N = 46) negative correlation was observed between the concentration of SP1 in serum and the concentration of estrogen receptor in the tumor. The longitudinal study of patients in stage 2 indicated that, of the 15 whose SP1 concentration fell below 1 microgram/1 after operation, 14 survived over 4 years whereas during the same period, 9 of the 10 patients whose SP1 value remained higher than 1 microgram/1 died.