【原】中国学者改进乳腺癌增殖指数分析方法

　　Ki67是由MKI67基因编码的蛋白质，与细胞增殖密切相关，有丝分裂期以及分裂间期的细胞Ki67表达水平极高，有丝分裂停止期的细胞Ki67表达水平极低。Ki67指数即肿瘤组织Ki67染色比例，对于乳腺癌具有结局预后和疗效预测的价值，而Ki67指数临界值是化疗前效果预测和化疗后效果评估的关键指标。不过，不同观察者对于Ki67定量的一致性较差，限制了Ki67的临床应用，尤其对于需要区分Ki67低表达的管腔A型乳腺癌与Ki67高表达的管腔B型乳腺癌。

　　2020年1月5日，欧洲乳腺癌专科医师学会《乳腺》在线发表中国人民解放军联勤保障部队第九二〇医院（原成都军区昆明总医院）、云南省肿瘤医院（昆明医科大学第三附属医院）、四川大学华西医院步宏、复旦大学附属肿瘤医院杨文涛等学者的研究报告，对Ki67定量方法进行了改进，并比较了不同观察者的一致性。

　　该研究首先从第九二〇医院和云南省肿瘤医院病理数据库随机选择100例原发乳腺浸润癌手术标本，进行福尔马林固定石蜡包埋组织切片Ki67免疫染色，放大20倍扫描为数字化切片，随后发送至16家医院实验室的41位病理科医师，根据染色分布进行分区划定后，通过半自动计数、目测法定量、数字化图像分析进行Ki67指数定量。最后，根据组内相关系数（ICC）和平均值差异离散图（Bland-Altman plot）分析不同观察者的一致性，根据威尔科克森（Wilcoxon）符号秩检验（每对数据差值正负及大小）比较半自动计数与数字化图像分析的Ki67指数差异。

　　结果，根据染色分布进行分区划定后，Ki67染色均匀或集中的切片与染色分散的切片相比，不同观察者的一致性显著较高。

　　根据染色分布进行分区划定后，半自动计数与目测法定量相比，不同观察者的一致性较高（ICC：0.942比0.802）。

　　根据染色分布进行分区划定后，半自动计数与数字化图像分析相比，Ki67指数显著较高：

• 差值为负（数字化图像分析<半自动计数）：N=80，秩和=4274.50

• 差值为正（数字化图像分析>半自动计数）：N=17，秩和=478.50

• Z=-6.837（P<0.001）

　　因此，该研究结果表明，根据染色分布进行分区划定后，半自动计数与目测法定量或数字化图像分析相比，不同观察者对于乳腺癌Ki67定量的一致性令人满意，并且可能成为乳腺癌或其他恶性肿瘤Ki67指数定量的候选标准化方法。

相关阅读

• Ki67增殖指数可以作为芳香酶抑制剂新辅助治疗乳腺癌无效后的化疗决策工具

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• 乳腺癌分子亚型和Ki67表达对中国人群新辅助化疗预后和效果预测的价值

• Ki67在三阴性和非三阴性乳腺癌中的表达及疗效预后分析

• 增殖细胞核抗原Ki67与乳腺癌新辅助化疗疗效的关系

• Ki67在三阴性乳腺癌中的临床病理意义

• 三阴性乳腺癌每周紫杉醇＋卡铂新辅助化疗前后Ki-67表达水平的意义

• Ki-67在三阴性乳腺癌中的预后和预测价值

• Ki-67与乳腺癌临床病理特征及新辅助化疗疗效的相关性

Breast. 2020 Jan 5;49:225-232. [Epub ahead of print]

An interobserver reproducibility analysis of size-set semiautomatic counting for Ki67 assessment in breast cancer.

Yi-xing Wang, Yuan-yuan Wang, Cheng-gang Yang, Hong Bu, Wen-tao Yang, Li Wang, Wen-mang Xu, Xi-long Zhao, Wen-xing Zhao, Lei Li, Shu-ling Song, Ju-lun Yang.

920th Hospital of Joint Logistics Support Force of PLA, Kunming, Yunnan, China; Yunnan Cancer Hospital, Kunming, Yunnan, China; West China Hospital, Sichuan University, Chengdu, China; Fudan University Shanghai Cancer Center, Fudan University, Shanghai, China.

HIGHLIGHTS

• A modified method for Ki67 LI assessment based on digital image, size-set semiautomatic counting (SSSAC).

• Investigated the interobserver reproducibility of SSSAC for Ki67 LI assessment of 100 cases in 41 pathologists of 16 hospitals.

• SSSAC has better interobserver reproducibility than current visual assessment and was more accurate than DIA in Ki67 assessment.

• SSSAC is a better choice for Ki67 LI assessment.

PURPOSE: The proliferation marker Ki67 has prognostic and predictive values in breast cancer, and the cutoff of the Ki67 label index (LI) is a key index for chemotherapy. However, poor interobserver consistency in Ki67 assessment has limited the clinical use of Ki67, especially in luminal cancers. Here, we reported a modified Ki67 assessment method, size-set semiautomatic counting (SSSAC) and investigated its interobserver reproducibility.

METHODS: One hundred invasive breast cancer tissues were set immunostained for Ki67 in one laboratory, scanned as digital slides, and sent to 41 pathologists at the laboratories of 16 hospitals for Ki67 LI assessment using size-set semiautomatic counting (SSSAC), size-set visual assessment (SSVA) and size-set digital image analysis (SSDIA) with a specific image viewing software (Aperio Image Scope, Leica, Germany). The intraclass correlation coefficient (ICC) and Bland-Altman plot were used to evaluate interobserver reproducibility. The Wilcoxon signed-rank test was used to analyze the difference in the Ki67 values assessed by SSSAC and SSDIA.

RESULTS: SSSAC demonstrated better interobserver reproducibility (ICC = 0.942) than SSVA (ICC = 0.802). The interobserver reproducibility was better in Ki67 homogeneously stained slides and centralized hot-spot slides than in scattered hot-spot slides. The Ki67 value assessed with SSSAC was obviously higher than that assessed with SSDIA (negative ranks (SSDIA < SSSAC): N = 80, sum of ranks = 4274.50; positive ranks (SSDIA > SSSAC): N = 17, sum of ranks = 478.50; Z = -6.837; P < 0.001).

CONCLUSION: SSSAC shows satisfactory interobserver reproducibility in the Ki67 assessment of breast cancer and may be a candidate standard method for Ki67 LI assessment in breast cancer and other malignancies.

KEYWORDS: Ki67 label index; Breast cancer; Immunochemistry; Assessment; Reproducibility

DOI: 10.1016/j.breast.2019.12.009