Alkaline phosphatase (alp) levels in multiple myeloma and solid cancers with bone lesions: Is there any difference?

Bone involvement in Multiple Myeloma results from increased osteoclast formation and activity that occurs in proximity to myeloma cells. The role of Alkaline Phosphatse (ALP) in this process and the diagnostic significance of plasma levels in patients with MM are unclear.

To compare plasma ALP levels in patients with MM and solid cancers and metastatic lesions to the bone.

In this observational retrospective study we enrolled 901 patients were enrolled: 440 patients (49%) with Multiple Myeloma, 461 (51%) with solid cancers. All 901 patients had bone lesions. Among patients with Multiple Myeloma, ALP values were mainly in the range of normality than those observed in patients with solid cancers and bone lesions. This difference is independent of stage, number and type of bone lesions.

This study suggests that plasma ALP has a different clinical significance in MM than in other neoplasms and could be used as a discriminating marker in presence of bone lesions. In particular, lower or normal values, should suggest further investigations such as urinary and serum electrophoresis, associated with bone marrow aspirate in case of the presence of a monoclonal component, in order to confirm or exclude a MM diagnosis.