The Expression Of Lrig1 Gene In Gastric Carcinoma Tissue And Peripheral Blood, And Combined Detection Between Lrig1 And Cancer Biomarkers

Objective To study the expression and the clinical significance of Lrig1 and EGFR in human gastric carcinoma and venous blood, and to analyze the diagnostic value of combined detection of Lrig1 and cancer biomarker CEA and CA724 for gastric carcinoma.Methods Immunohistochemistry was used to detect the expression of Lrig1 and EGFR proteins in 57 cases of gastric carcinoma tissues and normal gastric tissues, and analyze it with the clinical pathological parameters; detect the expression level of Lrig1 and EGFR m RNA in 57 cases of gastric carcinoma tissues and in corresponding non-tumor normal tissues, and the expression level of Lrig1 m RNA in the venous blood of 57 patients with gastric carcinoma and healthy human by RT-PCR; assay the expression level of CEA and CA199 in the serum of 57 patients with gastric carcinoma and healthy human by ECL, and analyze the result combine with the expression level of Lrig1 m RNA in the venous blood.Results 1. The positive expression rate of Lrig1 in gastric carcinoma tissues(38.6%)is lower than that in normal gastric tissue(82.5%), while the positive expression rate of EGFR in gastric carcinoma tissues(63.2%) is obviously higher than that in normal gastric tissues(15.8%), and the difference was statistically significant(P<0.05). The expression level of Lrig1 and EGFR in gastric carcinoma tissues is significantly negative correlation(r=-0.515, P<0.01). The expression of Lrig1 proteins have nothing related with patient’s age, gender, size or degree of differentiation of tumor, TNM stage or whether there is lymph node metastasis or not(P>0.05).The expression of EGFR shows no correlation with the age、sex and the tumor size(P>0.05),and have significantly positive correlation with the differentiation 、TNM staging and lymph node metastasis(P<0.01). 2. The expression level of Lrig1 m RNA in gastric carcinoma tissues(0.43 ± 0.16) is lower than those in corresponding non-tumor normal tissues(1.06 ± 0.21), while the expression level of EGFR m RNA(3.27 ± 0.67) is higher than in corresponding non-tumor normal tissues(1.33 ± 0.28), P<0.05. The expression of Lrig1 and EGFR m RNA in gastric carcinoma tissues showed a significant negative correlation(r =-0.874, P <0.01). 3. The expression level of Lrig1 m RNA in the venous blood of patients with gastric carcinoma(0.73 ± 0.21) is lower than that of the healthy control group(1.28 ± 0.27), P<0.05. 4. The level of CEA(39.6 ± 16.5) and CA724(58.8 ± 19.6) in the serum of patients with gastric carcinoma is significantly higher than the level of CEA(3.3 ± 1.2) and CA724(4.5 ± 1.7) of the healthy control group, P <0.05. The positive expression rate of CEA(54.4%), CA724(73.7%) in the serum of patients with gastric carcinoma is significantly higher than the healthy control group with the positive rate of CEA(14.0%), CA724(8.8%), while the the positive expression rate of Lrig1 m RNA in venous blood(49.1%) is significantly lower than that of the control group(87.7%). The expression level of Lrig1 in the venous blood of patients with gastric carcinoma showed negative correlation with the expressionlevel of CEA and CA724 in venous blood of patients with gastric carcinoma(r =-0.509, P <0.01; r =-0.369, P <0.01). The sensitivity and specificity of the combined detection of Lrig1, CEA and CA724 are higher than the those of single test.Conclusions 1. The expression of Lrig1 in gastric carcinoma tissues is negatively correlated with the expression of EGFR in gastric carcinoma tissues, suggesting that Lrig1 may have a negative feedback regulation of EGFR, and the they keep a certain balance in normal circumstances. 2. There is a low expression of Lrig1 in gastric carcinoma tissues, while there is a high expression of EGFR gastric carcinoma tissues, suggesting the low expression of Lrig1 decreases its negative feedback of EGFR, as a result of which the EGFR is activated thereby promoting a uncontrolled cell growth leading to the gastric carcinoma, and also suggesting that Lrig1 may have the effect of anti-oncogene in the development process of the gastric carcinoma. 3. Cancer biomarker CEA and CA724 have a certain sensitivity and specificity of gastric carcinoma, and combined detection with Lrig1 m RNA significantly raises the sensitivity and specificity of CEA and CA724 for gastric carcinoma, which has a high reference value in the early stage of prevention of gastric carcinoma.