Insulin-like growth factor 1 receptors in human breast cancer and their relation to estradiol and progesterone receptors.
Insulin-like growth factor 1 (IGF1) binding sites were characterized in breast cancer. We demonstrate the presence of one high affinity binding site. Chemical cross-linking of 125I-IGF1 to breast cancer membranes in reducing condition and sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed one band with an apparent molecular weight of 130,000. The specificity of the binding was studied. IGF2 was a good competitor whereas insulin competed with a potency lower than 1/100 that of IGF1. This IGF1 binding corresponded to the previously described type 1 IGF receptor (IGF1-R). IGF1-R was determined in 76 human breast cancer biopsies. Ninety-three % of the tumors were positive. The specific binding range was 0-16.4%; the geometric IGF1-R mean level was 3.9%. There was a relation (chi 2 test) between IGF1-R and progesterone receptor positivity rates (P = 0.002). The IGF1-R concentrations were correlated (Spearman test) with those of estradiol receptor (P = 0.0018) and progesterone receptor (P = 0.0011). A positive linear correlation existed between IGF1-R and estradiol receptor (P = 0.006) and between IGF1-R and progesterone receptor (P = 0.003). Our demonstration of the presence of IGF1-R in human breast cancer biopsies suggests that IGF1, acting either via the endocrine, paracrine, or autocrine pathways, could stimulate tumor growth.
Peyrat
J P
JP
Centre Oscar Lambret, Lille, France.
Bonneterre
J
J
Beuscart
R
R
Djiane
J
J
Demaille
A
A
D001706:Biopsy; D001943:Breast Neoplasms / Q000032:analysis*; D005260:Female; D006801:Humans; D011972:Receptor, Insulin / Q000032:analysis*; D011959:Receptors, Estradiol / Q000032:analysis*; D011980:Receptors, Progesterone / Q000032:analysis*; D017451:Receptors, Somatomedin; D013002:Somatomedins / Q000378:metabolism*
D011959:Receptors, Estradiol; D011980:Receptors, Progesterone; D017451:Receptors, Somatomedin; D013002:Somatomedins; D011972:Receptor, Insulin