Association of superoxide dismutases and NAD(P)H quinone oxidoreductases with prognosis of patients with breast carcinomas.

Associations of transcript levels of oxidative stress-modifying genes SOD2, SOD3, NQO1 and NQO2 and their functional single nucleotide polymorphisms (SNPs) rs4880, rs1799895, rs2536512, rs699473, rs1800566 and rs1143684 with prognosis of breast cancer patients were studied. SNPs were assessed by allelic discrimination in a cohort of 321 breast cancer patients from the Czech Republic. Transcript levels were determined by real-time polymerase chain reaction (PCR) with absolute quantification in tumor and adjacent non-neoplastic control tissues. Both genotypes and transcript levels were then compared with available clinical data on patients. Patients carrying low activity allele Leu in NQO2 rs1143684 had a greater incidence of stage 0 or I disease (i.e., better prognosis) than patients with the Phe/Phe genotype. This association was more evident in patients without expression of progesterone receptors (p = 0.031). Patients carrying the Thr allele in SOD3 rs2536512 SNP had a significantly greater incidence of tumors expressing estrogen receptors than patients carrying the Ala/Ala genotype (p = 0.007). SOD3 transcript level was significantly higher in grade 1 or 2 tumors than in grade 3 tumors (p = 0.006). Patients carrying T allele in SOD3 rs699473 SNP had significantly poorer progression-free survival (PFS) than patients carrying the CC genotype (p = 0.038). The same applied to the subgroup of patients treated by hormonal regimens (p = 0.021). Patients carrying the high activity Ala/Ala genotype in SOD2 (rs4880) had significantly poorer PFS than Val allele carriers in the group treated by cyclophosphamide but not hormonal regimens (p = 0.004). Our results suggest that NQO2, SOD2 and SOD3 may significantly modify prognosis of breast cancer patients and that their significance should be further characterized.

RNA expression of cytochrome P450 in breast cancer patients.

BACKGROUND: The expression pattern of cytochrome P450 genes (CYPs) affected by tumorigenesis may have an important role in the progression of cancer and in the metabolism of anticancer drugs. The aim of the study was to determine the expression patterns of four cytochrome P450 genes (CYP1B1, 2C9, 2E1 and 3A4) in breast cancer patients. PATIENTS AND METHODS: mRNA expression was quantified by real-time PCR. Analyses of 40 sets of human breast tumors, adjacent non-tumor tissues and of 18 peripheral blood lymphocyte samples were performed. Expression levels were tested for correlation with clinical and pathological data of patients. RESULTS: Expression levels of CYP2C9 and CYP3A4 were negligible. CYP1B1 expression was on average 50-fold higher than that of CYP2E1 with overexpression detected in one third of the tumors. Correlation of CYP1B1 expression in lymphocytes with that in non-tumor tissues was found. Significantly higher CYP2E1 expression was associated with an invasive lobular type of tumor, locally advanced disease as well as with non-tumor tissue of progesterone receptor-negative patients. CONCLUSION: CYP2E1 expression has a potential role as a breast cancer prognosis marker. The observed high CYP1B1 expression in tumor cells may evoke changes in their response to drugs which are substrates of P450 1B1 and influence metabolism or activation of environmental carcinogens.

Case report: type 1 diabetes in monozygotic quadruplets.

Type 1 diabetes (T1D) is an autoimmune disease characterized by the lack of insulin due to an autoimmune destruction of pancreatic beta cells. Here, we report a unique case of a family with naturally conceived quadruplets in which T1D was diagnosed in two quadruplets simultaneously. At the same time, the third quadruplet was diagnosed with the pre-diabetic stage. Remarkably, all four quadruplets were positive for anti-islet cell antibodies, GAD65 and IA-A2. Monozygotic status of the quadruplets was confirmed by testing 14 different short tandem repeat polymorphisms. Serological examination confirmed that all quadruplets and their father suffered from a recent enteroviral infection of EV68-71 serotype. To assess the nature of the molecular pathological processes contributing to the development of diabetes, immunocompetent cells isolated from all family members were characterized by gene expression arrays, immune-cell enumerations and cytokine-production assays. The microarray data provided evidence that viral infection, and IL-27 and IL-9 cytokine signalling contributed to the onset of T1D in two of the quadruplets. The propensity of stimulated immunocompetent cells from non-diabetic members of the family to secrete high level of IFN-α further corroborates this conclusion. The number of T regulatory cells as well as plasmacytoid and/or myeloid dendritic cells was found diminished in all family members. Thus, this unique family is a prime example for the support of the so-called 'fertile-field' hypothesis proposing that genetic predisposition to anti-islet autoimmunity is 'fertilized' and precipitated by a viral infection leading to a fully blown T1D.

NAD(P)H:quinone oxidoreductase 1 Pro187Ser polymorphism and expression do not cosegregate with clinico-pathological characteristics of human mammary tumors.

OBJECTIVE: The aim of this study was to further clarify the recently reported role of NAD(P)H:quinone oxidoreductase 1 (NQO1) as a strong prognostic and predictive factor in breast cancer. METHODS: NQO1 transcript levels were monitored in mammary tumors by real-time polymerase chain reaction. NQO1 protein levels were immunohistochemically determined in formalin-fixed paraffin-embedded tissues. NQO1 polymorphism (Pro187Ser, rs1800566) was also assessed. Evaluation (N=52) and validation (N=53) sets were analyzed subsequently. RESULTS: Carriers of variant NQO1-Ser allele had significantly more frequently NQO1-negative protein expression (P=0.001) in both sets. NQO1 transcript levels in samples with negative protein expression were significantly lower than in those with positive NQO1 protein expression (P=0.007) in both sets. Patients with stages 0/I/II had more often positive NQO1 protein expression than patients with stages III/IV (P=0.022) in the evaluation set. Significant association between NQO1 protein expression and TP53 protein status was also found (P=0.037). However, both associations were not replicated by analysis of the validation set. Analysis of both sets combined did not show significant association of NQO1 protein expression either with stage (P=0.231) or with TP53 protein status (P>0.999). Thus, the results observed in the evaluation set were effects of small sample size. CONCLUSION: The role of NQO1 in human mammary gland carcinogenesis does not seem to be directly associated with classical clinico-pathological factors.

Single nucleotide polymorphisms in the multidrug resistance gene 1 (ABCB1): effects on its expression and clinicopathological characteristics in breast cancer patients.

OBJECTIVES: Resistance of tumor cells to multiple cytostatic agents is one of the major impediments of successful cancer chemotherapy. A large part of resistance of tumors to chemotherapy is caused by the ABC transporter P-glycoprotein encoded by the ABCB1 gene. The main aim of this study was to assess the prognostic value of ABCB1 genotype and phenotype in breast cancer. METHODS: Six ABCB1 single nucleotide polymorphisms (SNPs) were determined in 90 Czech breast cancer patients by a novel method that allows simultaneous assessment of multiple polymorphisms on a single electronic microarray. Expression levels of ABCB1 were quantified in tumor and nontumor samples of breast cancer patients by real-time PCR. T-test, analysis of variance and Fisher's exact test were used to analyze the effect of ABCB1 polymorphisms on ABCB1 expression levels and for the analysis of associations between ABCB1 expression, genotype and clinical and pathological characteristics. RESULTS: ABCB1 was expressed in 98.9% of the tumor and in 97.5% of the nontumor samples. ABCB1 was downregulated in 79.5% of tumors compared with the nontumor samples. No significant correlation was observed between ABCB1 mRNA expression levels and clinical and pathological characteristics. High frequencies of the variant alleles in ABCB1 exon 12 (1236C>T, 38.3%) and exon 26 (3435C>T, 54.0%) were observed. Individuals with variant alleles in exons 12 and 26 had significantly lower ABCB1 expression levels in their tumors. SNPs in exons 12 and 26 also correlated with estrogen receptor status of patients. CONCLUSION: ABCB1 SNPs may affect function of P-glycoprotein by influencing the expression level and modify breast cancer prognosis.