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Published on: January 19, 2019
The Frequency of PD-L1 Marker Expression in ER Positive, PR Positive, HER2 Negative Invasive Breast Carcinomas, and
Fereshteh Mohammadizadeh1, Tahereh Naraki2, Mahboubeh Vafaei2
1Department of Pathology, School of Medicine, Shahid Beheshti Hospital, Isfahan University of Medical Sciences, Isfahan, Iran.
Background:
The aim of this study was to investigate the expression of the PD-L1 marker in ER-positive, PR-positive, and HER2-negative breast carcinoma and examine its correlation with clinicopathological factors that affect prognosis in these patients.
Materials And Methods:
This cross-sectional descriptive-analytical study was conducted on paraffin-embedded tissue blocks from 50 invasive breast carcinoma patients. PD-L1 immunohistochemical staining was performed, and samples were examined to assess the membranous staining of tumor cells with the PD-L1 marker. ER, PR, and HER2 results were obtained from the pathology reports. The tumor proliferative index was divided into two groups: low proliferative index (<14%) and high proliferative index (= or >14%), based on the percentage of tumor cell nuclei with positive staining.
Results:
PD-L1 expression was negative in 44 (88%) and positive in 6 samples (12%). There was no significant difference in the mean age, tumor grade, and tumor proliferative index between the two groups (P value > 0.05). All positive PD-L1 samples belonged to the IDC tumor subtype with a mean tumor size of 6.33 ± 6.41 cm. In the negative PD-L1 group, 88.6% were IDC, 4.5% were ILC, and 6.8% were mixed tumor subtypes, with a mean tumor size of 2.79 ± 1.54 cm. Tumor subtype, tumor size, and axillary lymph node status showed no significant difference between the two groups (P value > 0.05).
Conclusion:
According to the results of this study, there is no relationship between the PD-L1 expression and well-known clinicopathological prognostic factors in ER-positive, PR-positive, and HER2-negative invasive breast carcinomas.
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