Biologic frontiers in multiple myeloma: from biomarker identification to clinical practice.

Since the mid-1990s, the multiple myeloma treatment landscape has evolved considerably, which has led to improved patient outcomes and prolonged survival. In addition to discovering new, targeted agents or treatment regimens, the identification and validation of biomarkers has the potential to further improve patient outcomes. The International Staging System relies on a number of biochemical parameters to stratify patients into risk categories. Other biologically relevant markers that are indicative of inherited genetic variation (e.g., single-nucleotide polymorphisms) or tumor-acquired genetic events (e.g., chromosomal translocations or mutations) have been studied for their prognostic potential. In patients with high-risk cytogenetics, plasma cells (PC) undergo genetic shifts over time, which may partially explain why high-risk patients relapse and are so difficult to treat. Although novel agents have improved treatment outcomes, identification of markers that will enable clinicians to determine which treatment is most appropriate for high-risk patients following initial diagnosis represents an exciting frontier in the clinical management of multiple myeloma. Biomarkers based on quantitating PCs or factors that are secreted from them (e.g., serum free light chain) may also help to risk-stratify patients with asymptomatic multiple myeloma. Eventually, identification of novel biomarkers may lead to the creation of personalized treatment regimens that are optimized to target clonal PCs that express a specific oncogenomic profile. Although the future is exciting, validation will be necessary before these biologic and molecular beacons can inform decision-making processes in a routine clinical setting.