The Ki67/Cd138 Ratio Independently Predicts Overall Survival In The Upfront Treatment Of Newly Diagnosed Multiple Myeloma

Background: Assessment of malignant plasma cell cycling via plasma cell labeling index (PCLI) has been a validated prognostic tool in multiple myeloma (MM) but the test requires specialized technical expertise and is not widely available. Ki67 is a well-known protein marker of cellular proliferation on immunohistochemical (IHC) staining with prognostic utility in other malignancies. In an effort to develop a simpler system to provide analogous information to PCLI, we used a novel IHC co-staining technique for CD138 and Ki67 to quantify plasma cells in active cycling. We then performed a retrospective analysis of the ratio of Ki67/CD138 (Ki67%) in newly diagnosed patients with multiple myeloma receiving 1st-line therapy to correlate with clinical outcomes.