Abstract
Background: Breast cancer is a highly serious disease in which early diagnosis presents a critical step to successful therapy. At present time, identification of reliable prognostic markers that enable more precise estimation of disease progression is a major scientific target.
The group of biotransformation enzymes quinone oxidoreductases (NQO1 and NQO2) seems to be among such targets, as their association with breast cancer risk has been already published. Methods and Results: Expression of NQO1 and NQO2 was detected by real-time PCR in 42 paired tumor and surrounding (without morphologically verified presence of tumor cells) tissue samples and in 19 samples of lymphocytes of breast cancer patients.
Large inter-individual variability in expression of both genes was found along with deregulation in tumor tissue. Statistical comparisons of expression levels of both genes with clinical and histopathology findings were performed.
Postmenopausal patients had significantly higher NQO1 expression in their non-tumor samples when compared to premenopausal ones (P = 0,036). Higher NQO1 expression in non-tumor samples was found in patients without axillary lymph node metastasis (P = 0,044) and in patients with immunohistochemically detected expression of the estrogen receptor (P = 0.020) and progesterone receptor (P = 0,040).
Generally, high NQO1 expression in non-tumor tissue correlated with factors of good prognosis. This trend should be further verified by survival analysis from a long-term perspective.
Lower NQO2 expression was observed in tumor tissues of patients with invasive duct carcinomas of the mammary gland (P = 0.011). Conclusion: Expressions of NQO1 and NQO2 correlate with well-established prognostic factors in breast carcinoma patients and should be studied further on larger number of patients.