Expression And Clinicopathologic Features Of HER2 In Gastric Cancer

Background and Purpose:Gastric cancer(GC) is one of the most common malignancies and harms people's life and health. Especially, 5 year survival rate remains low in patients with advanced GC. Along with to the tumor member foundation unders- tanding's unceasing deepening, the molecular targeted therapy which control tumor development through suppress tumour cell's growth and multiplication has received gradually the attention. There is mounting evidence of the role of HER2 overexpression in patients with GC, and it has become solidly a hot spot of the molecular targeted therapy. At present, HER2 has already widely developed in breast cancer's research and the clinical medicine's application is also quite common, but it needs further study in terms of treatment of GC. ToGA tiral is the largest global phase III randomized clinical trial to evaluate the efficacy and safety of trastuzumab, an anti-Her2 monoclonal antibody, in the first-line treatment of advanced and metastatic GC. In the tiral, the researchers found that therapeutic effect of trastuzumab for HER2 2 + and 3 + of immunohistochemical scores is better. Some scholars believe that the reason is trastuzumab plays direct role on HER2 protein, therefore, HER2 protein immunohistochemical detection is the most direct and effective method to determine whether to carry on trastuzumab treatment. In the sebject , we investigated the expression of HER2 in GC using immunohistochemistry and analyzed the correlation between overexpression of HER2 and clinicopathological features and biological behavior .Methods:Collect 200 cases of GC which confirmed by pathological diagnosed and surgically treated and 30 cases of normal gastric tissue from July 2010 to January 2011 in the First Hospital of Jilin University .We detect HER2 expression in GC and normal gastric sue by immunohistochemistry assay(S-P method). Induce the clinicopathological data in HER2-positivity GC ,such as distribution of age, sexuality, turmor position, turmor size, depth of invasion, Lymph node metastasis,TNM stage and so on. Then statistically analyze the clinicopathologic parameters using SPSS 17.0. The measurement material uses the chi-square test, a probability of 0.05 was considered to represent a statistically significant difference.Results:1.In 200 specimens of GC,the positive expression rates of HER2 were 21.0%(42/200) .In 30 specimens of normal gastric tissue,the positive pression rates of HER2 were 3.3%(1/30).There are the significant difference between two groups (P<0.05).2.According to primary tumor site, Our study showed a 30.8% vs 17.6% HER2 overexpression in GEJ and in GC, respectively. HER2 expression is more common in GEJ cancers than in GC (p<0.05). According to Lauren type,we observed a higher rate of HER2 overexpression in intestinal than in diffuse type (28.5% vs 9.9%, p=0.01). In well and moderately differentiated,poorly differentiated GC,the positive expression rates of Her2 were 30.6%,15.6% respectively,difference is significant. (p<0.05)3. The overexpression rates of HER2 in GC without lymphatic node metastasis were 12.7%, and that with lymphatic node metastasis were 24.5%, the difference is remarkable, although does not have statistically significant difference (p=0.056). According to the TNM stage, positive expression rates of Her2 were 12.9% in I/II stage , comparely, these were 25.4% in III/IV stage , p<0.05. 4 Overexpression of HER2 protein is also shown in early GC. The expression rates is 17.8%, comparely, that in advanced GC(21.9%), does not have statistically difference (p>0.05). The overexpression rates of HER2 in early GC with lymphatic node metastasis were 7.7%, and that without lymphatic node metastasis were 1.8%, the difference is significant(p<0.05).Conclusions:1. Overexpression of HER2 protein is shown in GC.2. A higher rate of HER2 positivity in GEJ cancers than in gastric tumors(body or antrum). HER2 has a higher overexpression rate in the intestinal type GC than in the diffuse type GC. HER2 has a higher overexpression rate in well and moderately differentiated GC than in In well and moderately differentiated GC.3. A higher rate of HER2 positivity in GC with lymphatic node metastasis than in GC witjout lymphatic node metastasis. HER2 has a higher overexpression rate in the III/IV stage GC than in the other stage GC.4. Overexpression of HER2 protein is also shown in early GC. A higher rate of HER2 positivity in early GC with lymphatic node metastasis than in early GC without lymphatic node metastasis.