Abstract 80P
Background
Trop-2 is a transmembrane glycoprotein calcium signal transducer expressed in human epithelial cells and its increased expression has been linked with tumor growth and poorer prognosis in a variety of solid epithelial tumors. Trop-2 has been extensively evaluated in metastatic breast cancer with scarce data in earlier settings of the disease.
Methods
Cross-sectional study evaluating TROP-2 protein expression by immunohistochemistry (IHC) in patients with non-metastatic luminal breast. After the initial slide preparation process, the optimal antibody dilution for IHC of 1:100 was used (Trop-2 Antibody (B-9): sc-376746; Santa Cruz Biotechnology Inc., Dallas, TX, USA). The following categorization was used for readings for tumor cells: H-Score 0-<100 low, H-Score 100-200 intermediate and H-Score >200-300 high. Statistical analysis of the study was be performed using SPSS version 20.0 (IBM Germany). The expression profile of the Trop-2 biomarker was described by percentage and absolute frequency, respecting the scores for determining high, intermediate and low expression. Comparison of the markers described above with clinicopathological parameters was performed using Fisher's exact test. A value of P≤ 0.05 was considered statistically significant.
Results
Eighty-four patients were included in the study. The median age was 57, 70% of tumors were non special type ductal invasive carcinoma, 75% were T2, 47.6% were node negative and Trop-2 is highly expressed in 56% and medium expressed in 38% of patients. Trop-2 expression was correlated with well known clinical and pathological prognostic factors such as age (p=0.319), histological subtype (p=0.290), grade (p=0.806), Ki67 (p=0.940), tumor size (p=0.505), nodal status (p=0.505), lymphovascular invasion (p=0.519), tumor subtype (p=1.00), pathological staging (p=0.594) and prognostic staging (p=0.978). No evidence of association among Trop-2 biomarker and clinicopathological factors was found.
Conclusions
Trop-2 is a constitutional biomarker in Early Luminal Breast Cancer expressed independently of other characteristics and probably could be a target for personalized medicine in this clinical setting.
Legal entity responsible for the study
Prof. MD,PhD Marcia Silveira Graudenz.
Funding
The Hospital de Clinicas de Porto Alegre (HCPA).
Disclosure
All authors have declared no conflicts of interest.