Relationship between the ultrasound features of different molecular subtypes of breast cancer and positive PD-1/PD-L1 expression.

Abstract

Objectives: To analyze differences in programmed cell death protein 1/ligand 1 (PD-1/PD-L1) expression, as well as the relationships between ultrasound/contrast-enhanced ultrasound characteristics and PD-1/PD-L1 expression, among invasive breast cancer molecular subtypes.

Methods: The study included 172 invasive breast cancer patients with surgical resection and pathological confirmation at the First Affiliated Hospital of Xinjiang Medical University from June 2016 to April 2022. PD-1/PD-L1 expression was detected by immunohistochemistry. All patients underwent conventional ultrasound and some underwent contrast-enhanced ultrasound examination before resection.

Results: PD-1 and PD-L1 were expressed in 112 and 121 cases, respectively. The luminal B and HER-2 subtypes had the lowest and highest PD-1 expression rates, respectively. The luminal B and triple-negative subtypes had the lowest and highest PD-L1 expression rates, respectively. Among 112 PD-1-positive cases, most luminal B cases exhibited ill-defined margins, while distant metastasis was more common in triple-negative cases. Among 121 PD-L1-positive cases, many HER-2-positive and triple-negative cases presented as large masses (diameter ≥ 2 cm), while luminal B cases were more likely to show calcification. Most luminal B PD-L1-positive cases displayed indistinct margins on contrast-enhanced ultrasound.

Conclusions: PD-1 expression differed among molecular subtypes of invasive breast cancer. Ultrasound/contrast-enhanced ultrasound features correlated with PD-1/PD-L1 expression in different breast cancer subtypes.