| Background Gastric cancer is a common malicious tumors, which threatens human health. China is a high-prevalence area of gastric cancer and its new cases are over 40% of the global total new cases. Most of the gastric cancer patients in China are diagnosed at their middle and late stages, which brings huge challenges for clinical treatment. Trastuzumab treatment is a very promising therapy for the HER-2 positive patients. Studies have shown that the expression level of HER-2 varies between the biopsy and surgery specimens. The accurate evaluation of HER-2 expression level becomes extremely important for patients unavailable to surgeries.Aims The project is supposed to detect the HER-2 expression level in gastric cancer biopsy specimens through immunohistochemistry and compare with that in surgery specimens.Methods We have assessed 322 gastric cancer biopsy specimens and 390 gastric cancer surgery specimens, including 101 cases with both biopsy and surgery specimens. All the specimens were covered in wax, sectioned serially and stained with H.E. and HER-2 immunohistochemistry. Chi-Square test was used to analyze the relationship between HER-2 expression and cancer locations, histological types or lymphatic metastasis of gastric cancer surgery specimens, respectively. HER-2 expression in surgery specimens was used as the golden standard to analyze the consistency of HER-2 expression in biopsy and surgery specimens.Results 1. 11.5%(37/322) of the biopsy specimens are HER-2 positive and 15.8%(51/322) express HER-2 2+; while 4.4%(17/390) of surgery specimens are HER-2 positive and 10.0%(39/390) express HER-2 2+. 2. HER-2 expression is relevant to gastric cancer locations. In gastric surgery specimens, HER-2 over-expression(2+ and 3+) is detected in 10.1% of distal stomach(including antrum, angular incisure and pylorus), 19.9% of stomach body and 24% of proximal stomach(including cardia and fundus), which is gradually increased and statistically different(P=0.014). 3. HER-2 expression is relevant to histological types of gastric cancer. HER-2 over-expression is detected significantly higher(P<0.001) in well-differentiated gastric cancer specimens(28.7%, including high and moderately differentiated adenocarcinoma) than in poor-differentiated gastric cancer specimens(9.0%, including poorly differentiated adenocarcinoma, signet-ring cell carcinoma, mucinous adenocarcinoma and undifferentiated carcinoma). 4. HER-2 over-expression and lymph node staging are of no relevance(N0 16.3%, N1 12.3%, N2 17.8%, N3 a 14.2%, N3 b 5.2%). 5. The general consistency of HER-2 expression in biopsy and surgery specimens is 75%(76/101), including 22 biopsy specimens with higher HER-2 expression and 3 with lower expression. If HER-2 2+ and 3+ are considered to be HER-2 positive, general consistency is 77.2%, negative consistency is 95.9%, positive consistency is 39.4%, sensitivity is 88.5% and specificity is 76.5%.Conclusion:1. HER-2 over-expression is relevant to gastric cancer locations and histological types but non-relevant to lymph node staging. 2. It is accessible for the patients unavailable to surgery to screen for gastric cancer by detecting the HER-2 expression level in the biopsy specimens. Furthermore, in order to increase the accuracy of biopsy, we need to collect and store gastroscopic biopsy specimens standardly as well as choose lower HER-2 value when hard to decide. Current To GA standard still needs improvements in practical application. |
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