A Case of Chronic Myelogenous Leukemia with Abnormal Expression of N-CAM (CD56) Adhesion Molecule on CD34-negative Non-blastic Myeloid Cells / 대한진단검사의학회지

ABSTRACT

The CD56 antigen is a cell adhesion molecule and its expression on tumor cells is thought to play a role in CD56-positive lymphomas and leukemias with unusual sites of involvement. As to chronic myelogenous leukemia (CML) and related blastic crisis, CD56 expression is not generally considered as a part of the CML phenotype and has rarely been reported in CML and other chronic myeloproliferative dirsorders (CMPD). We reported a case of CML expressing the CD56 antigen on the CD34-negative myeloid cells presented with extramedullary granulocytic sarcoma and examined the CD56 reactivity on bone marrow biopsy sections in 9 patients with CMPD. To assess the abnormal expression of the CD56 antigen on myeloid and progenitor cells from CMPD, immunohistochemical staining and flow cytometric analysis were performed on bone marrow biopsy sections and aspirate specimens, respectively. Of nine patients with CMPD, a case of CML in blastic crisis with extramedullary granulocytic sarcoma showed an abnormal expression of CD56 on CD34-negative myeloid cells. The expression of CD56 on CML myeloid elements seems to represent an aberrant phenomenon that could affect the pattern of tumor cell dissemination.