Elevated serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1) closely reflect tumour burden in chronic B-lymphocytic leukaemia.

The present study is the first to report elevated serum levels of soluble (s)VCAM-1 in B-cell chronic lymphocytic leukaemia (B-CLL). A large cohort of 106 untreated patients was studied. sVCAM-1 was compared to known prognostic serum markers (soluble (s)ICAM-1; lactate dehydrogenase, LDH; sCD23; thymidine kinase, TK; beta2microglobulin, beta2m). The serum levels of sVCAM-1 reflected tumour burden as expressed by Binet/Rai stages more closely than any other marker. sVCAM-1 also reflected the kinetics of the disease as revealed by lymphocyte doubling time. sVCAM-1 was the only one of the studied markers which showed elevated levels in smouldering disease compared to controls. sVCAM-1, sICAM-1 and sCD23 (but not LDH, TK, beta2m) separated smouldering from non-smouldering B-CLL. Only sICAM-1, sCD23 and TK added independent prognostic information for survival to that of stage and lymphocyte doubling time. The expression of both adhesion molecules was examined in lymph node and splenic specimens. VCAM-1 and ICAM-1 were overexpressed by vascular endothelium and stroma, but the intensity of expression correlated poorly with serum levels of the soluble molecules. In conclusion, serum levels of sVCAM-1 correlated with tumour burden and other prognostic markers in B-CLL. VCAM-1 was overexpressed in tumour tissue as was ICAM-1. sVCAM-1 could prove a valuable marker in younger early-stage patients eligible for therapeutic trials.