Prognostic Significance Of Ki67 Expression By Immunohistochemistry (Ihc) On Bone Marrow Biopsy In Newly Diagnosed Multiple Myeloma

Background: Multiple myeloma (MM) is known to be a heterogeneous disease encompassing several molecular subtypes that can be defined either by means of genetic or molecular testing. In the multigene tests, the ‘PR’ subtype enriched with proliferation-related genes has a substantial impact on the prediction of the risk of MM recurrence. Ki-67 is a nuclear protein involved in cell cycle regulation and is considered an indicator of proliferation. It is present in dividing cells during all active phases of the cell cycle (S, G1, G2 and mitosis phases) and is distinctly absent in resting or quiescent (G0) cells. Ki67 expression has been widely used as an index to evaluate the proliferative activity of breast cancer and lymphoma but the impact of Ki-67 expression on the clinical outcomes of patients with MM has largely been unexplored. This study aimed to investigate whether Ki-67 expression by IHC is an indicator of outcome in MM patients, especially those treated with novel therapies combined with or without autologous stem cell transplantation.