Association between occludin gene expression and clinical morphological characteristics in breast cancer

Breast cancer is the second most common cancer in the world after lung cancer also is the fifth cause of cancer mortality. About 90 percent of cancer mortality is because of metastasis and devastating between cell attachments, especially tight cell junctions. Epithelial mesenchymal transition is a phenomena involved in metastasis and starts with cell detachment. Occludin is the integral membrane protein which is located in tight junctions. Obviously distressing tight junction, which facilitates the stages of metastasis in cancer cells are very critical step. The aim of this study was to demonstrate the importance of occludin expression and its relationship with invasiveness in human breast cancer. In a cross sectional study we evaluated 30 patients who were referred to Caner Institute of Imam Khomeini Hospital Complex, Tehran, Iran, from March 2013 to April 2013. Samples were derived from fresh frozen tumor of patients suffering from breast cancer after inform consent assignment in the Tumor Bank of Iran (TBI). RNA was extracted from tumor tissue followed by reverse transcription, polymerase chain reaction (PCR), conventional Real-time PCR and data analysis for the occludin gene expression. Data were analyzed based on clinical staging of breast cancer patients which were cited in data bank of TBI. Results of this study have demonstrated that the occludin gene expression was increased with the advanced stage. In 22 of patients the expression of gene was elevated compared with normal samples. On the other hand, the expression was significantly increased in stage II in comparison with stage I. The expression of occludin has increased by elevation of stage compared with normal tissue. It is suggested that alteration in the expression of this gene might be a possible factor which could affect on patient’s prognosis the same as other factors which are belonging to the same family. Increasing in expression of this gene might be considered as one of the possible markers which predict the possibility of invasion and metastasis.