Expression Of LETM1 In Gastric Cancer And Its Correlation With Prognosis

ObjectiveTo compare the expression difference of Leucine zipper-EF-hand containing transmembrane protein 1(LETM1)in gastric cancer and its adjacent normal tissue,and analyze the relationship between LETM1 and clinicopathological features and overall survival of patients,so as to evaluate the value of LETM1 as a new tumor marker in early clincal prognosis of gastric cancer.MethodsThe clinicopathological data and paraffin blocks of gastric cancer patients admitted to the hospital from July 2012 to December 2015 in Hospital were collected.114 cases of gastric cancer and corresponding adjacent normal tissues were stained by immunohistochemistry and the expressions of LETM1 in two different tissues were observed by microscopy.Then the score is graded by pathologists according to the staining to compare the expression difference of LETM1 between two tissues.According to the score criterion,the expression of gastric cancer tissue is divided high expression and low expression.The patient's clinical survival prognosis information was obtained by telephone follow-up.SPSS 19.0 was used for data entry and processing to analyze the relationship between LETM1 and clinicopathological features and 3-year overall survival rate of gastric cancer patients.Results(1)The results of immunohistochemistry staining showed that the expression of LETM1 was localized in the cytoplasm and gastric cancer tissue showed positive brown staining,while the expression of LETM1 in adjacent normal tissues was significantly lower or negative.The positive rates of LETM1 in gastric cancer and its adjacent normal tissues were 59.65%(68/114)and 15.78%(14/114),respectively,the difference was statistically significant(P < 0.05).(2)The expression of LETM1 in gastric cancer tissues was evaluated according to different clinicopathological factors.The assessment results showed that the expression of LETM1 was closely related to the differentiation degree(P=0.030),invasion degree(P=0.003)and lymph node metastases(P=0.033)of tumor,rather than the patient's age,gender and tumor size.Furthermore,the number of positive cells of gastric cancer tissues with pathological type of low differentiation,clinical stage III-IV and positive lymph node metastasis was significantly increased compared with that of gastric cancer tissues with pathological type of high or middle differentiation,clinical stage I-II and negative lymph node metastasis(P<0.05).(3)The analysis of prognostic results showed that the 3-year overall survival rate of gastric cancer patients with LETM1 positive expression was significantly lower than that of negative expression(x2=6.097,P=0.014<0.05).Survival analysis of subgroups showed that the 3-year overall survival rate of LETM1 expression was significantly different in gastric cancer patients with tumor size greater than 5 cm or lymph node metastasis positive or stage III-IV(P<0.05).Univariate survival analysis showed that the prognosis of gastric cancer patients was closely related to the expression level of LETM1,infiltration degree,differentiation degree,lymph node metastasis and tumor size(P<0.05),while the gender and age had nearly no effects on the prognosis of gastric cancer patients(P>0.05),Multivariate Cox regression analysis indicated that LETM1 is an independent factor of prognosis of gastric cancer.The lymph node metastasis,differentiation degree and infiltration degree of tumor are also independent prognostic factors(P<0.05),High expression level of LETM1,deeper extent of infiltration,higher differentiation degree,and positive lymph node metastasis are risk factors of poor prognosis in patients.Conclusions(1)The expression level of LETM1 in gastric cancer tissues was significantly higher than that in corresponding adjacent normal tissues.The expression of LETM1 was closely related to tumor TNM staging,lymph node metastasis and cancer cell differentiation.The expression level of LETM1 in gastric cancer patients with Low degree of pathological differentiation,later clinical TNM staging and lymph node metastasis was significantly higher than that in patients with high degree of pathological differentiation,earlier clinical TNM staging and no lymph node metastasis.(2)The expression level of LETM1,clinical TNM staging and lymph node metastasis are independent prognostic factors for gastric cancer patients.Hight level of LETM1 expression level,the later clinical TNM staging,and positive metastasis of lymph nodes can lead to poor prognosis.(3)The abnormal expression of LETM1 is closely related to the occurrence and development of gastric cancer,which can be used as a new biomarker for clinical prognosis of gastric cancer.