ASCO-SITC 2020: HLA Expression in Primary Lung Tumors and Brain Metastases
Posted: Friday, February 21, 2020
It appears possible to have discordant positivity in terms of human leukocyte antigens (HLA) being present or not in a single patient’s primary lung lesion and site of brain metastasis in those with metastatic non–small cell lung cancer (NSCLC). HLA is crucial for cytoxic T-cell responses to cancer, explained Jarrett Failing, MD, of the Mayo Clinic in Rochester, Minnesota, and colleagues. They presented their work at the 2020 American Society of Clinical Oncology–Society for Immunotherapy of Cancer (ASCO-SITC) Clinical Immuno-Oncology Symposium in Orlando (Abstract 43).
“There was no significant difference in the time between the primary tumor and brain metastasis resections in patients with HLA expression disagreement compared to those with HLA expression agreement,” pointed out Dr. Failing and colleagues. Further study is warranted, they suggested, because “differences in HLA expression may help explain the discrepancies in response to immune checkpoint inhibitors at different sites of disease.”
The researchers used an anti–HLA-A antibody to determine HLA-A cell membrane expression on tumor cells; tumors with greater than 10% HLA expression were considered to be positive. In 51 patients with paired primary NSCLC and brain lesions, the researchers found disagreement in HLA positivity between paired lesions in 11 patients (κ = 0.57; P = .0001) using agreement statistics and Fisher’s exact test for analysis. A total of 27 primary tumors and 24 brain metastases were HLA-positive, with a median HLA expression of 20% and 10% in the primary tumors and brain metastases, respectively.
Disclosure: The study authors reported no conflicts of interest.
