Rudhart SA, Schultz JD, Gehrt F, et al. - Since the clinical significance of cytokeratin fraction 21-1 (CYFRA 21-1) in patients with cutaneous squamous cell carcinoma (CSCC) in the head and neck is not known, researchers assessed the clinical value of CYFRA 21-1 in the treatment and follow-up for these patients. Between 2003 and 2017, they retrospectively analyzed the clinical, histological and laboratory data of a total of 55 patients with the first diagnosis of head and neck cutaneous squamous cell carcinoma (T1–T4, N0–N2b, M0–1). The ECLIA test kit was used to perform pretherapeutic determination of CYFRA 21-1 in all patients. Regional recurrence was discovered in 18 patients during therapy. Investigators found that the CYFRA 21-1 tumor marker is not clinically relevant for the therapy and follow-up of head and neck CSCC patients.