Lyn-Cook et al. demonstrated that NQO1 expression is higher in pancreatic adenocarcinomas compared to CB-5083 non-tumor tissues [22]. Wakai et al. demonstrated strong IHC staining of NQO1

in intrahepatic cholangiocarcinoma (ICC), whereas the non-tumor bile ducts and liver parenchyma were weakly stained. Cheng et al. showed that NQO1 expression is significantly increased in primary melanomas compared with dysplastic nevi and this may occur in the initiation stage of melanoma development [23]. A recent focus of current research has been the identification of polymorphisms in NQO1, which have been demonstrated as an increased risk of some tumors. Ouerhani et al. reported that the NQO1C609T genotype was overrepresented in acute lymphoblastic leukemia patients and was associated with an aggravating effect compared to the reference group with NQO1 C609C genotype [24]. Jamieson et al. BAY 1895344 research buy reported the NQO1 SNP (rs1800566) was associated with a poorer

outcome and a lower likelihood of having a treatment delay [25]. These findings indicated that NQO1 may have roles in carcinogenesis and tumor progression. However, the clinicopathological significance of NQO1 protein expression in breast cancer is less clear. In this study, we performed IHC staining of NQO1 protein in breast cancer tissue. In agreement with previous studies [13, 15], we found that staining of NQO1 is mainly localized in the cytoplasm, and these observations were consistent with our IF staining results in MCF-7 breast cancer cells. Compared with adjacent non-tumor tissues, NQO1 protein was found to be significantly up-regulated in breast cancer using IHC. PF-2341066 Western blot and qRT-PCR results also demonstrated that the mRNA and protein levels of NQO1 in four cases of fresh breast cancer samples were elevated compared with the adjacent non-tumor tissues. Furthermore, our IHC results showed that the positive rate of NQO1 protein in DCIS was also significantly higher than either hyperplasia or adjacent normal tissues, indicating that

NQO1 upregulation may occur in the initiation stage of breast Olopatadine cancer progression. These findings suggest that NQO1 protein level might be used as an early diagnostic indicator of this disease. Despite the strong association between NQO1 expression and cancer, there have been few reports of NQO1 protein expression-based outcomes in tumor patients. Mikami K et al. reported that the expression and enzyme activity of NQO1 is not only upregulated in colon cancer cell lines and colorectal tumors, but also significantly greater in tumors with nodal metastases than those without metastases [26], while Gan et al. reported higher expression of NQO1 protein in lower-grade and superficial bladder tumors compared with high-grade and invasive tumors [27]. In the present study, we found that the NQO1 expression level was markedly associated with histological grade (P = 0.004), clinical stage (P = 0.008), LN metastasis (P = 0.