Immunoradiometric assay of pS2 protein in breast cancer cytosols.
We studied the ELSA-pS2 immunoradiometric kit (CIS Bio International) for pS2 protein assay in breast cancer cytosols according to classic validation methods. In addition, we studied correlations between pS2, steroid receptors, and cathepsin-D assays. Repeatability (CV = 1.5% to 4.8%) and reproducibility (CV = 1.6% to 4.9%) were good. The results were linearly related to pS2 concentrations between 205 and 2200 ng/L; the detection limit was 40 ng/L. The accuracy of the assay was measured by assessing recovery; analytical recoveries were near 100% throughout the standard curve. The use of different compounds for cytosol preparation (Tris 10 mmol/L or phosphate 25 mmol/L, KCl 0.4 mol/L, bovine serum albumin 1 g/L) had no effect on pS2 results. pS2 was assayed in breast tumor cytosols from 197 postmenopausal and 92 premenopausal patients. The mean value was 24 micrograms/g of protein; the median and 25th and 75th percentiles were 6, 1, and 23 micrograms/g protein, respectively. We observed a relation between concentrations of pS2 and those of estrogen and progesterone receptors, but there was no relationship between the concentrations of pS2 and cathepsin-D.
Laboratoire d'Analyses Isotopiques, Centre François Baclesse, Caen, France.
J
J
Goussard
C
C
Lechevrel
G
G
Roussel
H
H
Cren
O
O
Bera
M
M
Sala
D001943:Breast Neoplasms / Q000378:metabolism*; D002402:Cathepsin D / Q000302:isolation & purification; D003600:Cytosol / Q000378:metabolism*; D005260:Female; D006801:Humans; D015592:Immunoradiometric Assay; D009363:Neoplasm Proteins / Q000378:metabolism*; D011506:Proteins; D011933:Reagent Kits, Diagnostic; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D000071163:Trefoil Factor-1; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins
D009363:Neoplasm Proteins; D011506:Proteins; D011933:Reagent Kits, Diagnostic; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C051838:TFF1 protein, human; D000071163:Trefoil Factor-1; D025521:Tumor Suppressor Proteins; D002402:Cathepsin D