Osteopontin is an adhesive factor for myeloma cells and is found in increased levels in plasma from patients with multiple myeloma.

Abstract

Myeloma cells produce OPN, and stromal cells from myeloma patients express higher levels of OPN than stromal cells from healthy controls. The myeloma cell lines ANBL-6 and INA-6 adhered to OPN. NOD/SCID mice inoculated with OPN-producing ANBL-6 cells had elevated levels of murine OPN in serum, whereas human OPN was not detectable. Plasma and serum levels of OPN were significantly higher in myeloma patients than in healthy individuals. Interpretation and Conclusions. Myeloma cell lines adhere to OPN, indicating that elevated stromal expression of OPN may be one of the factors responsible for the retention of myeloma cells in the bone marrow. The elevated plasma OPN levels in myeloma patients could be due to both production of OPN by the tumor cells and tumor-induced production of OPN by non-tumor cells.