Ki-67 Proliferative Index in The Non-Hodgkin’s Lymphoma and Its Clinical Significance

Abstract

Introduction: For prognostic purposes, it is of utmost importance to know the aggressiveness of the tumor. Ki-67 Proliferative index has been used in tumors of many organ systems as a potential marker to establish biological behavior and aggressiveness of the tumor. In Non Hodgkins lymphoma, there are controversial results in the literature, where most of the studies highlighting it as an important prognostic marker, while others reported to have no correlation with clinical or pathological parameter. The objective of study is to correlate Ki-67 proliferative index in tissue sections of Non-Hodgkins lymphoma with grade of lymphoma, NHL types and clinical parameters. Study Design: Descriptive Retrospective Study. Settings: Meezan lab, Faisalabad Pakistan. Duration: January 2015- December 2018 (4 years). Sample Size: 86 cases confirmed as NHL on IHC were taken and Ki-67 was evaluated. Sampling Technique: Non-probability consecutive sampling. Data Collection Procedure: 86 Paraffin-embedded tissue blocks of Non-Hodgkins lymphoma (NHL) cases, which were confirmed on Immuno-histochemistry were taken and Ki-67 immunostain was performed. Correlation of Ki-67 Proliferative index was done with immunophenotype, age, gender and site of origin. All the collected information was entered and analyzed using SPSS version 24. Chi-square calculator for 2x2 contingency table was employed to assess the relationship of clinical parameters like age, gender, lymphoma grade and site of origin with Ki-67 PI, taking cut off value of 45%. P value of < 0.05 was taken as significant. Results: 26 out of 30 cases of Extra-nodal lymphomas were having Ki-67 PI greater than 45% which was statistically significant with a p-value of 0.039731 (taking P-valve < 0.05 as significant). Similarly, aggressive lymphomas were statistically significant (P-value=0.000257) in staining ≥ 45 % of Ki-67 positive staining in tumor cells. Moreover, patients with age less than 30 years were shown to have ≥ 45 % Ki-67 positivity in lymphomas (p value= 0.00458). However, gender was not related to Ki-67 positivity with insignificant results (p value=0.8201). Conclusion: There was significant association of high Ki-67 Proliferative Index (>45%) with the aggressiveness of the lymphoma. Extranodal origin and age <30 years of age was also associated with high Ki-67 PI. However, no relationship was established between gender and Ki-67 expression.