Immunocytological Detection of Cytokeratin 18-positive Cells in Bone Marrow Aspirates in Non-small Cell Lung Cancer with Reference to Adhesion Molecule Expression

In order to detect cancer cells in the bloodstream, we analyzed cytokeratin 18-positive cells in bone marrow aspirates obtained from 64 patients with non-small cell lung cancer （NSCLC） （adenocarcinoma 50, squamous cell carcinoma 10, large cell carcinoma 4） by immunocytochemical method using CK2 （monoclonal antibody to cytokeratin 18）. The immunohistochemical expression of adhesion molecules was studied in 35 resected NSCLC tissues. Cytokeratin 18-positive cells in bone marrow aspirates were detected in 34 of the 64 patients. The detection rate of cytokeratin 18-positive cells in bone marrow aspirates correlated with the grade of T factor, and that rate was significantly high in patients with nodal or distant metastasis when compared with patients without the above metastases. The β1 integrin subunit was found in almost all NSCLC specimens, and α2, α3, α5, α6, αV and β4 subunits, intercellular adhesion molecule-1 （ICAM-1） and CD44 were frequently expressed and a minor popupation of tumors had expression of α1 and α4 subunits. The detection rate of cytokeratin 18-positive cells in bone marrow aspirates of the α2 subunit positive group （11/15） was significantly higher than that of the α2 subunit negative group （5/20） （p