Metastasis Initiating Cells in Renal Cancer
Mohammed I. Khan, Anna M. Czarnecka, Renata Duchnowska, Wojciech Kukwa and Cezary Szczylik
Metastasis is a complex process that propagate cells from the primary or initial site of the cancer occurrence to the distant part of the body. Cancer cells break from the cancer site and circulate through the bloodstream or lymph vessels and able to reach nearly all parts of the body. These circulating tumor cells (CTCs) contain specialized metastasis-initiating cells (MICs) that reside in the biological heterogeneous primary tumor. It has been hypothesized that metastasis of renal cell carcinoma is initiated by circulation of MICs in the blood and bone marrow of patients. Based on cancer stem/progenitor cell concept of carcinogenesis, understanding the molecular phenotypes of metastasis-initiating cells (MICs) in renal cancer could play a vital role in developing strategies for the therapeutics interventions in renal cancer. Existence of MICs among CTCs in renal carcinoma have not been proven experimentally in large scale. However, some studies reported that specialize markers are found on the surface of circulating cells from primary tumor. MICs can be isolated from CTCs using such markers and further can be transplanted into xenograft assay to show whether those give rise to metastasis in different organs in mice. Taking all these findings into consideration, in this review we have attempted to summarize the studies connected with MICs and their gene expression profile that are responsible for metastasis in renal cancer.
Molecular Oncology Laboratory, Clinic of Oncology, Military Institute of Medicine, ul. Szaserów 128, 04-141 Warsaw, Poland.