Immunohistochemical diagnostics in stomach cancer / Монголын Анагаах Ухаан

ABSTRACT

Although stomach cancer immunohistochemistry is similar tothe immunohistochemistry of other organ, it has great impact on diagnosis and treatment, such as its ability to reveal whether the cancer is primary or metastatic and which treatment model would be more effective in individual case. Lately, CK7, CK20 and CDX-2 immunohistochemical markers are commonly used in stomach cancers. Stomach cancer prognosis is different in each patient, depending on several factors, patients’ health status, cancer cell differentiation, and cancer cell growth. To evaluate these factors,immunohistochemic al analysis is more effective and for this purpose they use Ki-67, CD 34, BCL-2, p53, Cyclin D1, andHer- 2 markers.The evaluation of HER-2 expression should be carefully carried out, as following 1. HER-2 expression should be evaluated on minimum 5 positive stained cells. The evaluation criteria aremicroscopic magnification and cytoplasmic membrane-stained pattern. 2. Other than the membrane-stained pattern must be excluded. HER2 gene evaluation (FISH) can confirm the HER2 IHCexpression. 3. Usage of FDA approved antibody (4B5) has the advantageof increased sensitivity. 4. The algorithm for the evaluation of HER-2 expression used for breast cancer has 50% possibility of false negativity if it is used for stomach cancer. Therefore, it is needed to beevaluated with another specific algorithm. Because HER-2 2+ and 3+ cases can improve outcome with usingTrastizumab treatment.