EPCAM and head and neck squamous cell carcinoma: In a prospective study of locally advanced HNSCC patients treated with curative intent, the researchers have found that at the end of induction chemotherapy and concurrent chemotherapy, patients with PD-L1 mRNA over-expression in EpCAM(+) CTCs had shorter PFS and OS, so PD-L1 expression in EpCAM(+) CTCs is an independent prognostic factor for PFS and OS (84).