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  • Küçük Resim
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    Expression of CYP and GST in human normal and colon tumor tissues
    (Taylor & Francis Ltd, 2019) Bulus, H.; Oguztuzun, S.; Simsek, G. Guler; Kilic, M.; Ada, A. Oguz; Gol, S.; Iscan, M.
    We investigated the immunohistochemical staining characteristics of cytochrome P450 1A1 (CYP1A1), CYPB1, CYP2E1, and glutathione S-transferase P1 (GSTP1), GSTT1, GSTO1, GSTK1 in colon tumor and surrounding normal colon tissues. Tissues were obtained from 47 patients with colon adenocarcinoma and the staining intensity of tumor and control tissues was compared. CYP1A1, CYP1B1, CYP2E1, GSTP1, GSTT1, GSTO1 and GSTK1 expressions in colon cancer cells were significantly greater than those in normal colon epithelial cells. No significant relation was found between the isoenzyme expressions and age, gender, smoking status, tumor grade and tumor stage. The higher expressions of CYP1A1, CYP1B1, CYP2E1, GSTP1, GSTO1, GSTT1 and GSTK1 in tumor than in normal colon tissues may be important for colon cancer progression and development.
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    GST isoenzymes in matched normal and neoplastic breast tissue
    (Aepress Sro, 2011) Oguztuzun, S.; Abu-Hijleh, A.; Coban, T.; Bulbul, D.; Kilic, M.; Iscan, M.; Iscan, M.
    The potential to metabolize endogenous and exogenous substances may influence breast cancer development and tumor growth. Therefore we investigated GST activity and the protein expression of glutathione S-transferases (GSTs) isoenzymes known to be involved in the metabolism of endogenous and exogenous carcinogens in breast cancer tissue to obtain new information on their possible role in tumor progression. The interindividual variation in the conjugation of 1-chloro-2,4-dinitrobenzene (CDNB) and of 1,2-epoxy-3-(p-nitrophenoxy) propane (EPNP) with glutathione (GSH) by cytosolic glutathione S-transferases (GSTs) were investigated in human breast matched normal and tumor samples. The GSTA, GSTM, GSTP and GSTT isoenzymes from the crude extracts of matched breast normal and tumor tissues in terms of their immunological properties using western blotting were compared. In most of the samples, the GST activities were higher in the tumor than in the normal cytosolic fractions against both CDNB and EPNP. In the western blotting analysis, it was proved statistically that in normal and tumor epithelial cells, there was difference between GST pi and theta isoenzymes expressions (p<0.05), but no difference between the staining scores of GST mu and alpha isoenzymes (p>0.05). In normal epithelium there was a stronger GST theta expression than in invasive tumor tissues (p=0.013). However, the stronger GST pi expression was observed in tumor epithelium than in normal epithelium in human breast cancers (p=0.000). We found the GSTP protein level and GST activities were higher in the breast tumor than in the normal cytosolic fractions against both CDNB and EPNP, thus implicating a certain biological importance.