Cancer Metastases of 202 Kinds of Cancers via Cytocapsular Tubes

BACKGROUNDCancer metastasis is the primary source of solid cancer lethality, but the underlying mechanisms have essentially remained elusive. Recently, we found that cytocapsular tubes, a newly discovered organelle of mammalian cells, conduct cell translocation, suggesting an efficient pathway for cancer cell metastases. METHODSWe performed immunohistochemistry staining and fluorescence microscope imaging analyses of 6 kinds of normal organs (n=14 patients), 38 subtypes of benign tumors (n= 126 patients), and 8,061 clinical solid cancer tissue samples (covering 202 types and subtypes of cancers, and including cancers, paracancer tissues and metastatic cancers) taken from 7,125 cancer patients. These solid cancers cover 30 types of organs. We characterized cytocapsular tubes (CTs), cell migration in CTs, and CT quantity, density, network, superstructures and lifecycle in clinical samples of normal tissues, benign tumors, cancers, paracancer tissues, and metastatic cancers. RESULTSThere is no cytocapsular tubes (CTs) in normal organ tissues. Among the 126 benign tumor samples (covering 38 subtypes) from 126 patients, 86.6% do not have CTs and the other 13.4% show benign-to-malignancy transitions with CTs. Of the 8,061 solid cancer tissue and paracancer samples from 7,125 patients, 100% of cancers (including carcinomas in situ), 100% of paracancer tissues, and 100% of metastatic cancer tissues/organs, harbor large quantities (from thousands to hundreds of thousands) of CTs with many cancer cells in migration inside. CONCLUSIONCytocapsular tubes and networks provide membrane-enclosed physical freeway systems for clinical cancer cell metastasis to neighboring and far-distance tissues and organs.