ABSTRACT
An elevated serum ß2-microglobulin (ß2M) level is indicative of impaired glomerular filtration and prerenal diseases, such as malignant tumors, autoimmune disorders, and liver diseases. An elevated serum ß2M level has been shown to promote metastasis via the induction of epithelial-mesenchymal transition (EMT) in cancer cells. However, the therapeutic potential of targeting ß2M remains unclear. Here, we aimed to investigate the efficacy of Filtor, a small polymethyl methacrylate fiber-based ß2M removal column, in reducing the ß2M level and suppressing cancer cell-induced EMT and metastasis. We assessed the effects of Filtor on the changes in metastasis based on the number of circulating tumor cells (CTCs), which reflects the post-EMT cancer cell population. We performed therapeutic apheresis using Filtor on a male patient with sinonasal neuroendocrine carcinoma, a female patient with a history of colorectal cancer, and another female patient with a history of pancreatic ductal adenocarcinoma. Significantly low serum ß2M levels and CTC counts were observed immediately and 4 weeks after treatment compared with those in the pretreatment phase. Moreover, the CTC count immediately after therapeutic intervention was markedly reduced, likely because Filtor had trapped CTCs directly. These findings suggest that therapeutic apheresis with Filtor can prevent cancer metastasis and recurrence by directly removing CTCs.
