Measurement of glut-1 expression using tissue microarrays to determine a race specific prognostic marker for breast cancer

Background. African-American women (AAW) have more adverse tumor characteristics than non-African American women (non-AAW) and there is a need for a specific predictive marker for AAW recurrence. Tumors with higher grade and proliferative activity are associated with overexpression of the glucose transporter (Glut-1). An examination of Glut-1 expression relative to recurrence and no recurrence was conducted on both groups to determine if it predicts prognosis and could predict a race specific prognosis. Methods. A breast cancer data set containing clinical information including race and biological characteristics was generated between 1991 and 1996. Tissue samples were selected from this group with similar characteristics in both racial groups for a retrospective analysis of Glut-1 expression using tissue microarrays (TMAs). Mean Glut-1 expression for intensity and percent of tumor cells staining was determined using standard immunohistochemistry. Results. Clinical and biological differences were noted in the original data set between AAW and non-AAW. No significant difference between races was noted in mean Glut-1 values using a subset which had similar characteristics. The mean Glut-1 did not predict recurrence but a rounded score did indicate that higher levels of Glut-1 expression was indicative of a lower disease free survival (p = 0.063). The actual average mean for AAW with no recurrence was significantly lower than any other group (p = 0.04). Conclusions. TMA analysis for Glut-1 expression may be useful to predict disease free survival but it does not predict race specific recurrence.