Insulin-like growth factor-I receptor expression and localization in benign and malignant rat mammary tumors.

COCCA C; RANDI A; GUTIÉRREZ A; NÚÑEZ M; CROCI M; MARTÍN G; CRICCO G; MEDINA V; MOHAMAD N; RIVERA E; KLEIMAN D; BERGOC R

Anticancer Reserch

Año: 2005 vol. 25 p. 4305 - 4312

0250-7005

The aim of this study was to investigate the expression and localization of the insulin growth factor type 1 receptor (IGF-IR) in malignant and benign mammary tumors induced in rats by N-nitroso-N-methylurea (NMU) and its correlation with histopathology and hormone dependence. Also, protein tyrosine kinase activities (PTKs) were analyzed in order to study the activation of the intracellular cascade. The results showed that IGF-IR is present in NMU tumors (analyzed by binding assay and Western blot), that a variable content is expressed in tumors that continued growing post-ovariectomy (OVX) of rats, and that it is undetectable in tumors that regressed post-OVX. IGF-IR was principally localized (by immunohistochemistry) in the epithelial cells of malignant tumors and in the fibrous cells of benign ones. Also, a significantly lower expression of both cytosolic and microsomal PTKs were found in benign tumors. Our results suggest a different expression and role of IGF-IR in benign and malignant tumors.