Researchers have established a myeloid index score (MIS) that identified patients with melanoma with more aggressive disease, according to the results of their study published in the Journal for ImmunoTherapy of Cancer. Use of the score may help to tailor therapeutic choices for patients at higher risk of aggressive melanoma.

Using frozen peripheral blood mononuclear cells from 143 patients with stage IIIc to IV melanoma, the researchers assessed the relevant or redundant expression of myeloid and myeloid-derived suppressor cells (MDSC)-related markers using flow cytometry.

The identified panel was later applied to 59 patients undergoing therapy and validated in an additional 61 patients.


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The MIS was composed of 4 cell subsets: CD14+, CD14+HLA-DRneg, CD14+PD-L1+, and CD15+ cells). According to the researchers, these are all subsets “largely proved to be involved in cancer-related immunosuppression and disease aggressiveness.” Those patients with MIS of zero were found to have the best clinical outcomes, with median survival longer than 33.6 months.

In the screening group, patients with an MIS from 1 to 3 saw overall survival decreased from 10.9 months to 6.8 months to 6.0 months as the score increased (P <.0001). The hazard ratio for overall survival was 5.85 for MIS 1, 12.71 for MIS 2, and 32.63 for MIS 3. Use of MIS also grouped patients into risk groups according to progression-free survival, which indicates a “potential impact of the score on response/resistance to therapy as well.”

In the validation set, the correlation between MIS and survival was confirmed. The association was independent of the type of therapy and was not interfered by clinical prognostic factors.

MIS had the highest hazard ratio among all variables considered including lactate dehydrogenase, tumor burden, and neutrophil-to-lymphocyte ratio.

In their conclusions, the researchers proposed “the MIS as a tool to identify melanoma patients unlikely to benefit from current therapeutic strategies because of their systemic myeloid dysfunctions.”

Reference

Huber V, Di Guardo L, Lalli L, et al. Back to simplicity: a four-marker blood cell score to quantify prognostically relevant myeloid cells in melanoma patients. J Immunother Cancer. 2021;9(2):e00167. doi:10.1136/jitc-2020-001167