[Expression of serum GDF15 and its clinical significance in multiple myeloma patients]

To determine the serum level of the growth differentiation factor 15 (GDF15) in multiple myeloma (MM) patients and analyze its level with other clinical parameters, and to investigate its significance in the formation, development and prognosis assessment of MM.

We used enzyme-linked immunosorbent assay (ELISA) to measure the serum level of GDF15 in an MM group (24 pre-treatment patients) and in 20 healthy controls. All patients' clinical data were collected.

The serum GDF15 level was significantly higher in the MM group [(1.37±0.64) ng/mL] than in the normal control group [(0.14±0.06) ng/mL, P<0.01]. The mean serum GDF15 level in the MM patients in ISS stage III was (1.57±0.48) ng/mL, significantly higher than that of ISS stage (I+II) [(0.77±0.34) ng/mL, P<0.05]. There was no significant positive correlation between the serum GDF15 level and serum monoclonal proteins (M protein) level, β2-microglobulin and creatinemia (P<0.05), but significant inverse correlation was found between the GDF15 level with hemoglobin concentration and platelet count respectively (P<0.05). Serum GDF15 level was not associated with patients' age, albumin, lactic dehydrogenase (LDH), C-reactive protein (CRP), calcemia or leukocyte count (P>0.05). After 3 cycles of chemotherapy, patients with a>50% reduction of M protein had a significant reduction of GDF15, while for the patients whose M protein did not decrease obviously, their corresponding serum GDF15 level increased.

The serum GDF15 level may reflect the tumor burden in the MM patients, which increases obviously, is related with ISS, positively correlated with serum M protein level, β2- microglobulin level, serum creatinine and negatively with hemoglobin concentration and platelet count. The change of serum GDF15 level has some relation with the extent of M protein reduction, suggesting it may be used as a marker for therapy response.