phosphatase and tensin homolog gene are a tumor suppressor gene, and a key negatively regulator of cell signaling pathways that regulate growth and survival signaling pathways. Aim of study: Estimation the mPTEN in fresh breast cancer tissues versus apparently normal adjacent breast tissues in correlation with tumor marker Her/2 neu by immune histochemical staining. Patients and Methods: A prospective study, from January 2013 to January 2015. Fifty-pairs of fresh tissues from both breast cancer of invasive ductal carcinoma NOS and apparently normal adjacent tissues (from modify radical mastectomy) were by patients were recruited at the Surgical Department/Al-Diawania Teaching Hospital in Al-Diawania city. Total RNA extraction and real-time quantitative polymerize chain reaction technique were used for assessment of PTEN gene expression. Tissue sample present in the paraffin embedded blocks belonging to tumor and normal adjacent tissue were used for histopathology examination and for immunohistochemical staining for Her/2 neu. Results: All patients 50 (100%) exhibit PTEN gene expression down regulation, indicating fold change of cancer tissue for PTEN gene expression was significantly lower than that of normal adjacent tissue and the best cutoff value for gene expressional alteration in breast cancer tissues was (0.210) for diagnosis of gene alteration. Majority of cases (68%) were HER-2 negative. Conclusion: gene expression of PTEN was significantly altered in breast cancer tissues. It has been no significant associated between PTEN gene expression and protein expression for Her/2. How to Cite this Article Pubmed Style Shoroq Mohammed AL-Temimi and Adel Mosa AL-Rekabi. expression level of PTEN-gene is a diagnostic tool for gene alteration in invasive ductal carcinoma of the Breast. SRP. 2020; 11(10): 128-133. doi:10.31838/srp.2020.10.22 Web Style Shoroq Mohammed AL-Temimi and Adel Mosa AL-Rekabi. expression level of PTEN-gene is a diagnostic tool for gene alteration in invasive ductal carcinoma of the Breast. http://www.sysrevpharm.org/?mno=10528 [Access: March 29, 2021]. doi:10.31838/srp.2020.10.22 AMA (American Medical Association) Style Shoroq Mohammed AL-Temimi and Adel Mosa AL-Rekabi. expression level of PTEN-gene is a diagnostic tool for gene alteration in invasive ductal carcinoma of the Breast. SRP. 2020; 11(10): 128-133. doi:10.31838/srp.2020.10.22 Vancouver/ICMJE Style Shoroq Mohammed AL-Temimi and Adel Mosa AL-Rekabi. expression level of PTEN-gene is a diagnostic tool for gene alteration in invasive ductal carcinoma of the Breast. SRP. (2020), [cited March 29, 2021]; 11(10): 128-133. doi:10.31838/srp.2020.10.22 Harvard Style Shoroq Mohammed AL-Temimi and Adel Mosa AL-Rekabi (2020) expression level of PTEN-gene is a diagnostic tool for gene alteration in invasive ductal carcinoma of the Breast. SRP, 11 (10), 128-133. doi:10.31838/srp.2020.10.22 Turabian Style Shoroq Mohammed AL-Temimi and Adel Mosa AL-Rekabi. 2020. expression level of PTEN-gene is a diagnostic tool for gene alteration in invasive ductal carcinoma of the Reviews in Pharmacy, 11 (10), 128-133. doi:10.31838/srp.2020.10.22 Chicago Style Shoroq Mohammed AL-Temimi and Adel Mosa AL-Rekabi. The expression level of PTEN-gene is a diagnostic tool for gene alteration in invasive ductal carcinoma of the Breast. Systematic Reviews in Pharmacy 11 (2020), 128-133. doi:10.31838/srp.2020.10.22 MLA (The Modern Language Association) Style Shoroq Mohammed AL-Temimi and Adel Mosa AL-Rekabi. The expression level of PTEN-gene is a diagnostic tool for gene alteration in invasive ductal carcinoma of the Breast. Systematic Reviews in Pharmacy 11.10 (2020), 128-133. Print. doi:10.31838/srp.2020.10.22 APA (American Psychological Association) Style Shoroq Mohammed AL-Temimi and Adel Mosa AL-Rekabi (2020) expression level of PTEN-gene is a diagnostic tool for gene alteration in invasive ductal carcinoma of the Reviews in Pharmacy, 11 (10), 128-133. doi:10.31838/srp.2020.10.22