[223] Glucose Transporter Glut-1 Expression Correlates with Basal-Like Breast Cancer

YR Hussein, S Bandyopadhyay, Q Ahmed, T Jazaerly, B Albashiti, M Ibrahim, Z Nahleh, W Sakr, R Ali-Fehmi. Wayne State Univ, Detroit; Karmanos Cancer Institute, Detroit

Background: Basal-like breast cancer, i.e., ER-negative, PR-negative, Her-2-negative, and basal cytokeratin (CK5/6 and or CK14)-positive, is a high risk breast cancer that lacks the benefit of specific therapy. Glut-1 is a facilitative glucose transporter that is expressed in normal tissue and in higher levels in a number of malignancies. In previous studies, Glut-1 overexpression has been found in breast cancer and has been associated with higher grade and proliferative activity. The aim of our study was to characterize the immunohistochemical (IHC) expression of Glut-1 in the morphologic and molecular subtypes of invasive breast cancers.
Design: We identified 523 cases of invasive breast cancer from the pathology database between 2004 and 2006. The clinicopathologic findings and the biologic markers including ER, PR and Her-2 status were reviewed. IHC for CK5/6, CK 14, and Glut-1 were performed on tissue microarray using standard procedures. Positivity for Glut-1 was defined as cytoplasmic staining of more than 40% of tumor cells. Follow up for all the patients was obtained from our records (CIS) and SEER database. Statistical analysis using Chi square, Fisher's exact test, Kaplan Meier was done.
Results: We were able to morphologically classify 415 tumors as basal-like; 54 (10%), and non-basal-like cancers; 361 (90%). Glut-1 was overexpressed in 33 (67%) of basal-like tumors, whereas only 55 (24%) of the non-basal cancers showed increased expression for Glut-1 (p <0.0001).

The correlation between Glut-1 and basal-like breast cancer

Glut-1	Basal-like	Non-basal
No.of cases	49	231
Positive	33(67%)	55(23%)
Negative	16(33%)	187(73%)
p value	< 0.0001

Glut 1 overexpression correlated also strongly and significantly with tumor grade within the two categories. Among the poorly differentiated tumors, Glut-1 was significantly overexpressed in 29 (71%) of the basal –like cases, in contrast to the non-basal type which showed increased expression in 32(29%) cases only (p<0.0001). Furthermore, Glut-1 overexpression was associated overall with increase tumor size (p=0.04), however, there was no correlation between the overexpression of Glut-1 and patients outcome for the two subtypes.
Conclusions: We determined the overexpression of Glut-1 in basal-like in comparison to non-basal-like cancer. Glut-1 may serve as a potential prognostic marker and a therapeutic target in this aggressive subgroup of breast cancer.
Category: Breast

Monday, March 22, 2010 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 19, Monday Morning