Relationship Between HER2 Oncogene Amplification By Fluorescence In Situ Hybridization And Clinical Pathology Of Breast Cancer

Objective to study the relationship between HER2 oncogene amplification by fluorescence in situ hybridization(FISH) and clinical pathology of primary breast cancer,and to compare the consistency with those obtained by immunohistochemistry ( IHC) .Methods Collected 139 cases of fresh tissue samples of breast cancer in gastrointestinal gland surgery of first affiliated hospital of guangxi medical university from November 2007 to December 2009,all cases were pathologically confirmed as invasive ductal carcinoma, none of the neo-adjuvant chemotherapy, radiotherapy,endocrine therapy before surgery,and the physical score (ECOG)<1.Tumor tissue specimens were isolated in 10% neutral formalin within 1 hour after surgery, paraffin-embedded routinely.HER2 gene amplification and protein expression were respectively detected by fluorescence in situ hybridization (FISH) and conventional immunohistochemistry (IHC), and analyzed the relationship between HER2 and clinical-pathology using chi-square test,while analyzed the consistency between FISH and IHC using Kappa test.Resultsâ‘ In 139 cases of fresh breast cancer tissue,there are 53 cases of HER2 gene amplification by FISH detection,the positive rate was 38.1% (53/139);there are 34 cases of HER2 protein over-expression (+++) by IHC detection, the positive rate was 24.5% (34/139); The total coincidence rate of two methods was 52.5%. HER2-positive rate of FISH detection is higher than IHC testing, and have a close relationship between two kinds of detection methods(rs =0.675,p<0.05).â‘¡29 cases were HER2 gene amplification in 34 cases with HER2 protein over-expression (+++),the coincidence rate was 85.3%;18 cases were HER2 gene amplification in 31 cases with HER2 protein over-expression (++),the coincidence rate was 58.1%;52cases were HER2 no- gene amplification in 58 cases with HER2 protein over-expression (+),the coincidence rate was 89.7%;none case were HER2 gene amplification in 16 cases with HER2 protein over-expression (-),the coincidence rate was 100%;â‘¢HER2 gene amplification was relevant to HER2 protein overexpression (P <0.05), histological grade (P <0.05), number of lymph node metastasis (P <0.05), estrogen and progesterone receptor (P <0.05),but no relevant to age (P> 0.05), menopausal status (P> 0.05), tumor size (P> 0.05), clinical stage (P> 0.05), lymph node metastasis (P> 0.05). Conclusion HER2-positive rate of FISH detection is higher than IHC detection, there is a good consistency between FISH and IHC (kappa value is 0.525), the total coincidence rate is 52.5%. In which,there is a quite difference in HER2 protein expression (++) between IHC and FISH test results. Within HER2 protein expression (+++), there are still a small number of specimens without HER2 gene amplification (IHC false positive);Within the HER2 protein expression (+) samples, there is still a small number of HER2 gene amplification (IHC false-negative).So for the HER2 protein (++) ,there is a need to further clarify whether the HER2 gene amplification by FISH. For the HER2 protein (-~+) or (+++),FISH testing can also be considered to confirm whether the HER2 gene amplification.In this study,HER2 gene amplification is significantly correlated with the histological grading and hormone receptor status, suggesting that strong invasiveness of tumor cells, high malignant. HER2 is closely related with breast cancer development, treatment and prognosis,which can be used as the ideal target for treatment of Herecptin.