POU5F1B and neoplasm: Furthermore, POU5F1B-encoding transcripts have been detected in circulating but not primary tumor cells from pancreatic ductal adenocarcinoma (PDAC), where they have been found to be associated with a more rapid clinical deterioration52, suggesting that POU5F1B contributes to conferring PDAC cells with the phenotype of circulating and, ultimately, of metastasis-initiating cells (MICs)53.