Emerging Insights into Keratin 16 Expression during Metastatic Progression of Breast Cancer.

Keratins are the main identification markers of circulating tumor cells (CTCs); however, whether their deregulation is associated with the metastatic process is largely unknown. Previously we have shown by in silico analysis that keratin 16 (KRT16) mRNA upregulation might be associated with more aggressive cancer. Therefore, in this study, we investigated the biological role and the clinical relevance of K16 in metastatic breast cancer. By performing RT-qPCR, western blot, and immunocytochemistry, we investigated the expression patterns of K16 in metastatic breast cancer cell lines and evaluated the clinical relevance of K16 expression in CTCs of 20 metastatic breast cancer patients. High K16 protein expression was associated with an intermediate mesenchymal phenotype. Functional studies showed that K16 has a regulatory effect on EMT and overexpression of K16 significantly enhanced cell motility (p < 0.001). In metastatic breast cancer patients, 64.7% of the detected CTCs expressed K16, which was associated with shorter relapse-free survival (p = 0.0042). Our findings imply that K16 is a metastasis-associated protein that promotes EMT and acts as a positive regulator of cellular motility. Furthermore, determining K16 status in CTCs provides prognostic information that helps to identify patients whose tumors are more prone to metastasize

Liquid Biopsy for Investigation of Cancer DNA in Esophageal Squamous Cell Carcinoma

Early detection of cancer and the monitoring of cancer recurrence in treated patients are significant challenges in esophageal squamous cell carcinoma (ESCC). Liquid biopsy is the identification of tumor biomarkers from minimally invasive samples of biological fluids, including urine, blood, stool, saliva, or cerebrospinal fluid. Liquid biopsy offers a potential solution to the problems of detection and surveillance as DNA shed from cancer cells as cell-free DNA or in exosomes can be detected in body fluids. By detecting these DNAs, we can identify the presence of cancer-associated mutations for basic detection, as well as to obtain information on the recurrence and evolution of disease following initial treatment. These sources of information have the potential to significantly improve the management of patients with ESCC. In this chapter, we detail a method for the isolation of cell-free DNA from blood plasma and DNA associated with exosomes in blood from patients with esophageal squamous cell carcinomas.</p