ORIGINAL ARTICLE CYP1A1 and GSTP1 gene variations in breast cancer: a systematic review and case–control study Sumaira Akhtar 1 • Ishrat Mahjabeen 1 • Zertashia Akram 1 • Mahmood Akhtar Kayani 1 Ó Springer Science+Business Media Dordrecht 2015 Abstract In first part of this study, a systematic review was designed to explore the involvement of CYP1A1 and GSTP1 genes in breast cancerogenesis. Based on systematic review, we designed a study to screen CYP1A1 and GSTP1 genes for mutation and their possible association with breast carcino- genesis. A total of 400 individuals were collected and ana- lyzed by PCR-SSCP. After sequence analysis of coding region of CYP1A1 we identified eleven mutations in dif- ferent exons of respective gene. Among these eleven muta- tions, *3 folds increased breast cancer risk was found associated with Asp82Glu mutation (OR 2.99; 95 % CI 1.26–7.09), with Ser83Thr mutation (OR 2.99; 95 % CI 1.26–7.09) and with Glu86Ala mutation (OR 3.18; 95 % CI 1.27–7.93) in cancer patients compared to controls. Fur- thermore, *4 folds increase in breast cancer risk was found associated with Asp347Glu, Phe398Tyr and 5178delT mutations (OR 3.92; 95 % CI 1.35–11.3) in patients com- pared to controls. The sequence analysis of GSTP1 resulted in identification of total five mutations. Among these five mutations, *3 folds increase in breast cancer risk was observed associated with 1860G[A mutation, with 1861-1876delCAGCCCTCTGGAGTGG mutation (OR 2.70; 95 % CI 1.10–6.62) and with 1861C[A mutation (OR 2.97; 95 % CI 1.01–8.45) in cancer patients compared to controls. Furthermore, *5 folds increase in breast cancer risk was associated with 1883G[T mutation (OR 4.75; 95 % CI 1.46–15.3) and *6 folds increase in breast cancer risk was found associated with Iso105Val mutation (OR 6.43; 95 % CI 1.41–29.3) in cancer patients compared to controls. Our finding, based on systematic review and experimental data suggest that the polymorphic CYP1A1 and GSTP1 genes may contribute to risk of developing breast cancer. Keywords Xenobiotic metabolizing pathway  CYP1A1  GSTP1  Breast cancer  Mutations  SSCP Introduction A large number of studies have reported that genetic poly- morphisms involved in carcinogen metabolism may result in increased risk of cancer development including breast cancer [1–3]. These carcinogen metabolizing enzymes play an important role in activation/deactivation of various chemical agents, including xenobiotics and sex hormones [4]. These enzymes are divided into two main phases; phase I and phase II detoxifying enzymes that protect the cells from DNA damage by various reactive substances [5]. The Cytochrome P450 P1A1 (CYP1A1) is located at chromosome 15 (15q22-q24.1) and is included in phase I detoxification process. CYP1A1 is one of the three members of the Cytochrome P450 family, which is found mainly in extra- hepatic tissues and participates in the metabolism of a vast number of xenobiotics, as well as a small number of Electronic supplementary material The online version of this article (doi:10.1007/s10689-015-9849-1) contains supplementary material, which is available to authorized users. & Mahmood Akhtar Kayani mkayani@comsats.edu.pk Sumaira Akhtar sumi_8859@yahoo.com Ishrat Mahjabeen ishrat.mahjabeen@comsats.edu.pk Zertashia Akram zertashia.akram@comsats.edu.pk 1 Cancer Genetics Lab, Department of Biosciences, COMSATS Institute of Information Technology, Islamabad 44000, Pakistan 123 Familial Cancer DOI 10.1007/s10689-015-9849-1