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.