Objective: To determine the cut-off values of Ki-67 labeling index (LI) in the histological grading of follicular lymphoma (FL). Methods: Clinicopathological data of 350 FL patients diagnosed at Beijing Friendship Hospital from June 2014 to January 2016 were analyzed retrospectively by quantitative evaluation and statistical analysis of Ki-67 LI. Results: Of the 350 patients with FL, the male and female ratio was 1.1 and the average age was (50.2±14.0) years with a median age of 51 years (range 4 to 82 years). The tumors were graded as grade Ⅰ-Ⅱ in 215 cases (61.4%), grade Ⅲ A in 105 cases (30.0%), and grade Ⅲ B in 30 cases (8.6%). The average Ki-67 values were (22.8%±8.3%) for the FL low (grade Ⅰ-Ⅱ) and (50.4%±10.7%) for high grade (Ⅲ A and Ⅲ B) and were statistically significant by Mann Whitney U test (P<0.01). Receiver operated characteristic curve analysis showed that the best diagnostic cut-off value of low grade FL was 35% (sensitivity of 96.3% and specificity of 93.3%) with the largest area under curve (AUC=0.990, P<0.01, 95%CI for 0.982-0.998). According to the analysis of four lattice diagnostic tests, Ki-67 LI >40% was an important factor (χ2=230.733, P<0.01) in predicting high grade FL. When the cut-off value of Ki-67 LI was set at 40%, high grade LF could be diagnosed with the greatest sensitivity (98.1%) and specificity (87.7%). Moreover, a significant correlation between the Ki-67 LI and the pathological grade of FL (r=0.836, P<0.01) was observed. Conclusions: Ki-67 LI of below a cut-off value of 35% is a reliable indicator of low grade FL.Ki-67 over 40% is consistent with high grade FL. These Ki-67 cut-off values may serveas an important auxiliary indicator in the grading of FL.
目的： 探讨Ki－67阳性指数在滤泡性淋巴瘤(follicular lymphoma，FL)病理分级中的临界值。 方法： 回顾性分析2014年6月至2016年1月北京友谊医院病理科诊断的350例FL患者的临床病理学资料，对Ki－67阳性指数进行定量评估和相关统计分析。 结果： 在350例FL患者中，男女比例为1.1∶1.0，平均年龄(50.2±14.0)岁，中位年龄51岁(范围4～82岁)。病理分级Ⅰ～Ⅱ级215例(61.4%)，ⅢA级105例(30.0%)，ⅢB级30例(8.6%)。经Mann Whitney U检验，在FL低级别(Ⅰ～Ⅱ级)和高级别(ⅢA和ⅢB)中Ki－67阳性指数的平均值差异具有统计学意义[(22.8%±8.3%)比(50.4%±10.7%)，P<0.01]。受试者工作特征(ROC)曲线法分析，诊断FL低级别最佳的临界值为35%，敏感度为96.3%，特异度为93.3%，ROC曲线下面积(AUC)最大(AUC＝0.990，P<0.01，95%CI为0.982～0.998)。四格表诊断试验分析Ki－67阳性指数>40%是预测FL高级别的重要因素(χ2＝230.733，P<0.01)。Ki－67阳性指数临界值为40%时诊断为高级别FL有最大的灵敏度(98.1%)和特异度(87.7%)。Ki－67阳性指数与FL的病理分级呈显著正相关性(r＝0.836，P<0.01)。 结论： Ki－67阳性指数小于临界值35%是诊断FL低级别的可靠指标，>40%提示可能是高级别FL。Ki－67阳性指数的临界值可作为FL病理分级的依据或重要辅助指标。.
Keywords: Ki-67 antigen; Lymphoma, follicular; Lymphoma, non-Hodgkin.