Liver and bone metastasis may have different sensitivities to chemotherapy due to different microenvironments and biological characteristics, resulting in the ineffectiveness of chemotherapy.[26] Study found that in most patients, chemotherapy cannot completely eliminate different subsets of circulating tumor cells, including the CD56-positive circulating tumor cell subset, because some of these patients are sensitive to chemotherapy while others seem to be resistant to it. Here, NCAM1 is linked to neoplasm.