Breast Cancer Coverage from Every Angle

SITC 2021: Cellular Study of Malignant Pleural Effusions and Metastatic Breast Cancer

By: Vanessa A. Carter, BS
Posted: Wednesday, November 24, 2021

A pilot study performed by Caddie Dy Laberiano, MD, of The University of Texas MD Anderson Cancer Center, Houston, and colleagues evaluated the correlation between the immune landscape of malignant pleural effusions and their related clinicopathologic features in patients with metastatic breast cancer. Their results, presented during the 2021 Society for Immunotherapy of Cancer (SITC) Annual Meeting (Abstract 945), suggest that multiplex immunofluorescence may prove to be an effective tool to study these effusions, although further research is warranted.

The investigators collected 5 ┬Ám thick paraffin cell pellet blocks from six cases of breast carcinoma with malignant pleural effusions. Sections were stained for markers against DAPI, PD-L1, PD-1, Foxp3, pancytokeratin (CK), CD3, CD8, CD68, and Ki67 using quantitative multiplex immunofluorescence. A multispectral scanner was used to capture images and analyze the co-expression of these markers.

The median cellular density was 5,870.53 cells. Between malignant and reactive mesothelial cells, approximately 75.9% showed expression for CK positivity, and 8% of these cells were positive for Ki67; 0.2% were positive for PD-L1, and 0.7% demonstrated CD3 positivity.

Among cytotoxic T cells, the median co-expression of CD3 and CD8 positivity was 12.1%, whereas the co-expression of CD3 and PD-1 positivity without complementary PD-L1 expression was 1.1%. Additionally, CD68 positivity was present in 8.1% of the total cells.

Disclosure: No disclosure information was provided.

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