Expression of PD-L1 in medullary thyroid carcinoma-a new therapeutic target?

PD-L1 expression in MTC is hot topic since, if it is demonstrated that PD-L1 is highly expressed in this cancer, thus immunotherapy against checkpoint inhibitors could become an important therapeutic tool in MTC treatment. To answer this question, we evaluated PD-L1 expression in MCT tumour tissues, using an anti-PD-L1 22C3 antibody and found a high expression in 6 of the 8 patients (75%). Similarly, two other recent studies reported a higher PD-L1 expression. According to our results, MTC cells present a significative PD-L1 expression, raising the hypothesis that immunotherapy, such as pembrolizumab, could have a role on MCT treatment. The authors believe this is a fundamental question and may impact the future of MTC treatment.