Abstract P1-09-06: Metabolic coupling in phyllodes tumor of the breast and its correlation to tumor progression

Abstract

Background: Markers of metabolic coupling have been associated with clinical outcomes in numerous human cancers, including breast cancer. Loss of caveolin-1(CAV1) in stromal cells and upregulation of monocarboxylate transporters (MCTs), especially MCT1 and MCT4, in both stromal and cancer cells have been identified as playing an important role in the metabolic coupling necessary for release and uptake of metabolites. However, this phenomenon has been rarely described in phyllodes tumors (PTs) of the breast. Materials and methods: One hundred-one PTs (60 benign, 26 borderline, and 15 malignant) and 9 breast tissues with no pathological lesions were analyzed. Automated immunohistochemical staining for CAV-1, MCT1, and MCT4 was performed using tissue microarray blocks, and their expressions were assessed in both stromal and epithelial components. Results: Compared with normal breast, CAV-1 expression in PTs showed a significant decrease in stromal component (P < 0.001). MCT1 expression was significantly increased in both epithelial and stromal components of PTs compared to normal breast (P < 0.001 and P < 0.001, respectively). Stromal MCT1 and MCT4 expression was different according to the tumor grade of PTs and stromal MCT1 expression tended to increase with increasing tumor grade (P < 0.001). Although not statistically significant, stromal CAV-1 expression tended to decrease with increasing PTs grade. The recurrence rate was higher in the stromal MCT1-positive groups (19.2%, 14/73) than in the stromal MCT1-negative groups (3.9%, 1/28) (P < 0.05). Conclusions: This result suggested that changes of CAV-1, MCT1, and MCT4 may be associated with tumorigenesis and progression of PTs of the breast. Keywords Phyllodes tumor, CAV-1, MCT 1, MCT4, Metabolic coupling. Citation Format: Ji Shin Leee, Nah Ihm Kim, Min Ho Park. Metabolic coupling in phyllodes tumor of the breast and its correlation to tumor progression [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-09-06.