en Medical Genetics Medical Genetics Original Research Original Research <strong>Background: </strong>PI3K/Akt/mTOR pathway is a crucial pathway in the angiogenesis, tumour growth and cell differentiation of several cancers. The PI3K and KIT genes are key genes of this pathway. Previous studies have reported the importance of these genes in the development of gastrointestinal carcinoma, leukaemia, and melanomas. The role of mutations and overexpression of PI3K and KIT genes in breast cancer has been previously proved. This study investigates the correlation between PI3K and KIT gene mutations in sporadic breast cancer.<br> <strong>&nbsp;&nbsp; Methods:</strong> Multiplex Ligation-dependent Probe Amplification&nbsp;(MLPA) technique was used to determine the Copy Number Variation (CNV) of PI3K and KIT genes in 34 breast cancer tumours and PCR-sequencing was used to detect the mutation in PI3K exons 9 and 20.<br> <strong>&nbsp;&nbsp; Results:</strong> Our results reported that 27% of patients had CNV of the KIT gene; whereas, 20% and 17.5% of patients, had mutation and CNV in the PI3K gene, respectively. We did not found a significant correlation between the mutations of PI3K and KIT genes.<br> <strong>&nbsp;&nbsp; Conclusion: </strong>About two-tenth of the patients revealed CNV and lesser than two-tenth indicated mutation in the PI3K gene, whereas one-third of the patients demonstrated CNV in the KIT gene. Thus, administration of the PI3K and KIT gene inhibitor drugs might be proposed to suppress breast cancer in patients with mutation and CNV of each of these individual genes.<br> &nbsp; mTOR pathway, PI3K gene, KIT gene, Breast Cancer 789 793 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-3996-1&slc_lang=en&sid=1 Maryam Rahimi maryamrahimi1986@yahoo.com 200319475328460042514 200319475328460042514 No Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran Farkhondeh Behjati fbehjati@gmail.com 200319475328460042515 200319475328460042515 No Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran Nazanin Taheri ntaheri67@yahoo.com 200319475328460042516 200319475328460042516 No Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran Shadi Hosseini shadihosseini7@gmail.com 200319475328460042517 200319475328460042517 No Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran Hamid Reza Khorram Khorshid hrkhkh@yahoo.com 200319475328460042518 200319475328460042518 No Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran Fatemeh Aghakhani Moghaddam shahla@hotmail.com 200319475328460042519 200319475328460042519 No Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran Masoud Karimlou mkarimlo@yahoo.com 200319475328460042520 200319475328460042520 No Department of Epidemiology and Biostatistics, Tehran Medical Branch, Islamic Azad University, Tehran, Iran Saghar Ghasemi ghasemisaghar@gmail.com 200319475328460042521 200319475328460042521 No Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran Niloofar Bazazzadegan ni.bazazadegan@uswr.ac.ir 200319475328460042522 200319475328460042522 No Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran Fereidoon Sirati f.sirati@tums.ac.ir 200319475328460042523 200319475328460042523 No Cancer Institute, Department of surgery- Tehran University of Medical Sciences, Tehran, Iran Elahe Keyhani ekeyhani1058@gmail.com 200319475328460042524 200319475328460042524 Yes Genetics Research Center, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran