LRIG1 expression in colorectal cancer.
In the present study the expression of LRIG1 (leucine rich repeats and immunoglobin-like domains 1) and its relation to EGFR (epidermal growth factor receptor) was examined in tumour samples and adjacent non-neoplastic tissues from 30 patients with colorectal cancer. The LRIG1 gene, at chromosome 3p14, encodes an intergral membrane protein, which counteracts signalling by receptor tyrosine kinases belonging to the ERBB (epidermal growth factor receptor) family. LRIG1 is expressed in all tissues and organs analysed to date, including breast, brain, skin, kidney, spleen and colon. Overexpression of EGFR is seen in 70 - 90% of colorectal cancers, and is associated with a poor survival. Western blot analysis showed LRIG1 upregulation in 43% and downregulation in 43% of the colorectal cancers compared to adjacent non-neoplastic tissue. No correlation was evident between LRIG1, analysed by Western Blot and the expression of EGFR analysed by immunohistochemistry. FISH (fluoroscence in situ hybridisAtion) analysis showed increased LRIG1 copy number in one of nine tumours. Four colorectal cancer cell lines demonstrated two LRIG1 gene copies. In conclusion, there was a great heterogeneity in the expression of the LRIG1 protein in colorectal cancer, which was not related to gene dosage of the LRIG1 gene. Further studies can be of interest to evaluate whether alteration in LRIG1 expression in colorectal cancer is of biological or clinical significance.
Ljuslinder
Ingrid
I
Department of Radiation Sciences, Oncology, Umeå University Hospital, Umeå University, Umeå, Sweden. ingrid.ljuslinder@onkologi.umu.se
Golovleva
Irina
I
Palmqvist
Richard
R
Oberg
Ake
A
Stenling
Roger
R
Jonsson
Yvonne
Y
Hedman
Håkan
H
Henriksson
Roger
R
Malmer
Beatrice
B
D000230:Adenocarcinoma / Q000235:genetics* / Q000378:metabolism*; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism*; D066246:ErbB Receptors / Q000378:metabolism; D005260:Female; D005629:Frozen Sections; D018628:Gene Dosage; D015972:Gene Expression Regulation, Neoplastic; D019073:HT29 Cells; D006801:Humans; D008297:Male; D016555:Matched-Pair Analysis; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism*; D008875:Middle Aged; D014407:Tumor Cells, Cultured
C484445:LRIG1 protein, human; D008562:Membrane Glycoproteins; D066246:ErbB Receptors