LRIG1 amplification in breast cancer

Abstract

9627 Background: This study was conducted to investigate if the previously described human gene LRIG1 is of interest in the malignant process of breast cancer. The gene is the human homologue of mouse Lig-1 and is located on chromosome band 3p14.3, a region frequently deleted in human cancers and previous studies of 3p have implicated that a tumour suppressor gene might be located in the area. This gene encodes a transmembrane cell surface protein with extracellular leucine-rich repeats and immunoglobulin–like regions. LRIG1 mRNA and protein has been detected in various tissues, with average levels in breast tissue. Methods: The present study was to characterize the expression of LRIG1 in breast cancer by FISH, CGH, quantitative RT-PCR, Western Blot and immunohistochemistry. Two subgroups were analysed; one group consists of randomly taken tumour samples from 19 patients collected 1987–1995 and the other group included consecutively samples of tumours from 9 patients with parallel sampled non-neoplastic breast tissues for comparison Results: Amplification of LRIG1 was found in 11 of 28 (39%) of tumours, resulting in an overexpression of mRNA and protein. The amplification correlated with increased levels of mRNA and protein by RT-PCR and Western blot. Conclusions: Amplification of LRIG1 in chromosome 3p14.3 is a novel observation indicating a role of LRIG1 in breast cancer. No significant financial relationships to disclose.