Radioimmunoassay of laminin P1 in body fluids of pregnant women, patients with gynaecological cancer and controls.

Laminin P1, a pepsin-resistant fragment of the glycoprotein laminin, was determined in body fluids using a double-antibody radioimmunoassay. The median serum concentrations found were: men 1.32, premenopausal women 1.22, postmenopausal women 1.38 and pregnant women (35th gestational week) 2.18 U/ml. The median concentration in amniotic fluid was 1.90, in urine 0.28 and in follicle cyst fluid 1.74 U/ml. During gestation, rising serum levels of up to 5 U/ml were observed which decreased within a few days after delivery. The cut-off value of laminin P1 for 95% specificity of the normal female control group was found to be 1.8 U/ml. The frequencies of elevated serum concentrations were 11, 18, 23 and 33% in patients with primary malignant lesions of the breast, endometrium, cervix and ovary, respectively, and rose up to 50-51% in patients with recurrent or metastatic gynaecological cancer. Laminin P1 was found in high concentrations in the cytosol fractions of breast cancer biopsies. Long-term sequential determinations of serum levels in 10 individual patients with progressive cancer reflected the course of the disease in 8 cases. Although laminin P1 can be considered as a tumour-associated protein, low sensitivity to primary cancer and insufficient specificity limit its application as a tumour marker and its usefulness in monitoring of patients with gynaecological cancer.