The following is a summary of “PD-L1 and MCL-1 markers and the relationship with prognostic characteristics of differentiated thyroid carcinoma,” published in the June 2023 issue of Molecular and Cellular Endocrinology by Zantut-Wittmann et al.

MCL-1 and PD-L1 proteins are associated with mechanisms of carcinogenesis in differentiated thyroid carcinoma (DTC). Tumor antigens stimulate the expression of PD-1 in immune cells, which then attaches to PD-L1 on tumor cells, resulting in immune evasion of the tumor. MCL-1, a member of the BCL-2 family with anti-apoptotic properties, is required for the survival of T and B lymphocytes and has a high oncogenic potential. Researchers intend to assess the clinical utility and relevance of MCL-1 and PD-L1 in determining the prognosis of DTC over the long term. Included were 120 DTC patients who were followed for at least 2 years after total thyroidectomy and radioiodine therapy. 

MCL-1 and PD-L immunohistochemical expression and BRAFV600E mutation were related to demographic characteristics, tumor histopathology, persistence/recurrence risk, outcome-related factors, initial response to therapy, and persistence or disease-free status at the follow-up. Around 100(83.3%) were females; the mean age at diagnosis was 46.64±16.73 years; 37(30.8%) patients had a high disease recurrence/persistence risk, 45(37.5%) had intermediate risk, and 38(31.1%) had a low risk. At the end of 124.86 ±65.36 months of follow-up, 48 (42.5%) had persistent disease. About 103 patients (85.8%) had papillary thyroid carcinoma (PTC), while 17 patients (14.2%) had follicular thyroid carcinoma (FTC). BRAFV600E was associated with moderate/strong PD-L1 and MCL-1 expressions in PTC (P=0.0467; P=0.0044, respectively). PD-L1 was also associated with the subtype of tall cells (P=0.0274). The maximum nodule diameter was associated with low PD-L1 expression in FTC (P = 0.0100). 

Strong/moderate PD-L1 expression was associated with T2, whereas poor expression was associated with T3 in the TNM classification (P=0.0490). Smoking is associated with moderate MCL-1 expression (P = 0.0350). PDL-1, a marker of the progression of tumor cells, and MCL-1, an anti-apoptotic identification, were associated with PTC containing the BRAFV600E mutation, whereas PDL-1 was associated with a more aggressive subtype of PTC. MCL-1 and PD-L1 may be beneficial in constructing a panel to evaluate the prognosis of patients with PTC. However, both markers appeared to have less relevance for FTC patients.

Source: sciencedirect.com/science/article/abs/pii/S0303720723000825