Abstract
BACKGROUND/AIM: T-cell immunoreceptor with immunoglobulin (Ig) and immunoreceptor tyrosine-based inhibitory motif (ITIM) domains (TIGIT) is an immune checkpoint receptor involved in the immune evasion of malignant cells and a putative target for novel immunotherapies. TIGIT is expressed by tumor microenvironment (TME) cells in various types of lymphomas, including classical Hodgkin lymphoma (cHL). However, the TIGIT expression patterns in cHL and their relationship with clinical and laboratory parameters require further elucidation. PATIENTS AND METHODS: We studied the immunohistochemical expression patterns of TIGIT in tissue sections from 55 patients diagnosed with cHL. RESULTS: TIGIT was not expressed by Hodgkin and Reed-Sternberg (HRS) cells but was expressed in the TME cells of 45/55 (81.8%) cases. Using 10% as a threshold for positivity, TIGIT was expressed in the TME cells in 33/55 (60%) cases. Rosettes of TIGIT-positive TME cells around HRS cells were detected in 12/55 cases (21%). While TIGIT expression patterns showed no association with clinical outcomes, established laboratory parameters such as β2-microglobulin demonstrated a significant impact on overall survival. In summary, cHL exhibits frequent but highly variable TIGIT expression patterns in TME cells. CONCLUSION: These findings further support the concept of biological heterogeneity of cHL and encourage further studies assessing the role of TIGIT as a potential target for immunotherapy in cHL.