Ki-67 Immunostaining and its Correlation with Microvessel Density in Patients with Mutiple Myeloma

Purpose: To compare Ki-67 index and microvessel density MVD) in multiple myeloma and non-myeloma patients and their correlation with each other and other prognostic markers. Materials and Methods: Forty patients were enrolled in this study between 2011-2013, 30 with multiple myelomas and 10 with non-malignant disease as controls. Proliferative activity was analyzed by Ki-67 and microvessel density (MVC) was assessed by CD34 and compared between two groups. In myeloma patients, correlation between Ki-67, MVD and other prognostic factors was assessed by Pearson correlation coefficient. Results: According to Durie Salmon staging criteria, 13 patients were of stage 1, 5 of stage II and 12 of stage III. Ki-67 expression showed a positive correlation with MVD (r=0.729, <0.001) and was significantly higher (<0.0001) in myeloma patients (range 35-80%, mean 60.1 %) as compared to controls (range 8-25%, mean 18.1%). MVD/mm2 was also significantly (<0.0001) higher in myeloma patients (range 62-237/mm2, mean 178.0/mm2) than controls (range 5.2-50/mm2, mean 18.3/mm2). Ki-67 and MVD, both increased progressively with increasing stage of myeloma. Ki-67 showed significant positive correlation with blood urea and lactate dehydrogenase and a significant negative correlation with serum albumin. MVD showed a significant positive correlation with blood urea, lactate dehydrogenase, serum creatinine, 2 microglobulin and skeletal lesions. Conclusions: Ki-67 and MVD are indicators of aggressiveness and poor prognosis having significant correlation with each other and other prognostic markers of multiple myeloma. Routine assessment of these markers may help to identify high risk patients, who may benefit from with more aggressive therapy.