Soluble syndecan-1 at diagnosis and during follow up of multiple myeloma: a single institution study.
BACKGROUND
Syndecan-1 is a heparan sulfate proteoglycan expressed on plasma cells, especially myeloma cells, and can exist in serum as soluble syndecan-1 after shedding from the cell surface. Soluble syndecan-1 has been suggested to promote myeloma cell growth and to be an independent prognostic factor for multiple myeloma. We aimed to evaluate the effect of soluble syndecan-1 levels at the time of diagnosis and during therapy on therapeutic response and prognosis for patients with multiple myeloma.


METHODS
We analyzed soluble syndecan-1 levels in 28 patients with multiple myeloma and 50 normal controls, and compared its levels with Durie-Salmon stage and other markers of myeloma. In addition, we evaluated the therapeutic response and determined the 3-year survival rates of these patients.


RESULTS
We observed that the median soluble syndecan-1 level in myeloma patients was higher than that in the normal controls (P <0.0001), and the soluble syndecan-1 levels in 21 (75%) patients were higher than the cut-off level (162 ng/mL). Soluble syndecan-1 levels correlated with disease stage, percentage of plasma cells in the bone marrow, β(2) microglobulin level, serum M-component concentration, and creatinine level. The baseline levels of soluble syndecan-1 at the time of diagnosis in the patients who responded to chemotherapy were lower than those in the non-responders (P=0.04); however, the baseline level was not a significant predictor of therapeutic response. The 3-year overall survival rate of the patients with high soluble syndecan-1 levels at the time of diagnosis and 6 months after chemotherapy was lower than the corresponding survival rates of the patients with low levels of soluble syndecan-1; however, the overall survival rate was not statistically significant.


CONCLUSIONS
The use of soluble syndecan-1 has limitations in the diagnosis of multiple myeloma. Soluble syndecan-1 levels correlate with known prognostic factors; however, we could not assess the prognostic value of high levels of soluble syndecan-1 at the time of diagnosis and after chemotherapy.
Department of Laboratory Medicine, Eulji University Hospital, Daejeon, Korea.
Ji Myung
JM
Kim
Jung Ae
JA
Lee
In Sung
IS
Cho
Chun Hwa
CH
Ihm