Immune Profiling of Advanced Thyroid Cancers Using Fluorescent Multiplex Immunohistochemistry
Jonghwa Ahn, Meihua Jin, Eyun Song, Yeon‐Mi Ryu, Dong Eun Song, Sang‐Yeob Kim, Tae Yong Kim, Won Bae Kim, Won Bae Kim, Young Kee Shong, Min Ji Jeon, Won Gu Kim, Won Gu Kim
Abstract
Background: Advanced thyroid cancers, including differentiated thyroid carcinoma (DTC) with distant metastasis, and anaplastic thyroid carcinoma (ATC), are associated with poor clinical outcomes and limited treatment options. This study aimed to determine the immune profiles of advanced thyroid cancers using fluorescent multiplex immunohistochemistry (F-MIHC) and multispectral imaging (MSI). Methods: Twenty-eight tissue samples were collected from 12 patients who had DTC with distant metastasis and from 16 with ATC. The samples were assessed using F-MIHC and MSI with antibodies against the cell surface molecules, cluster of differentiation (CD)4, CD8, programmed cell death-1 (PD-1), PD ligand 1 (PD-L1), forkhead box protein 3, and cytokeratin (CK). The expression of PD-L1 was evaluated using tumor proportion score (TPS) and combined positive score (CPS). Results: Significantly, more PD-L1-positive tumor cells (CK + PD-L1 + ) per mm 2 were found in ATC samples than in DTC samples (183.5 vs. 0.03, p < 0.001). Lymphocyte infiltration was significantly increased in ATC compared with DTC, with significantly more PD-L1- or PD-1-positive lymphocytes in ATC samples than in DTC samples. The TPS and CPS for PD-L1 expression were negative in all DTC samples but positive in 81% and 94% of ATC samples, respectively. Conclusions: Immune profiling revealed significant differences between advanced DTC and ATC, particularly in terms of PD-L1 expression and lymphocyte infiltration. Therefore, immune profiling using F-MIHC and MSI can provide invaluable information regarding tumor microenvironments, which could help select candidates for immunotherapy.