MammaPrint versus EndoPredict: Poor correlation in disease recurrence risk classification of hormone receptor positive breast cancer

IntroductionCorrect risk assessment of disease recurrence in patients with early breast cancer is critically important to detect patients who may be spared adjuvant chemotherapy. In clinical practice this is increasingly done based on the results of gene expression assays. In the present study we compared the concordance of the 70-gene signature MammaPrint (MP) with the 12 gene assay EndoPredict (EP).MethodsRepresentative tissue of 48 primary tumours was analysed with the MP during routine diagnostic purposes. Corresponding formalin-fixed, paraffin-embedded tissue was thereafter analysed by the EP test. Risk categories of both tests were compared.Results41 of 48 tumours could be directly compared by both tests. Of the 17 MP low risk cases, only 9 were considered low risk by EP (53% agreement) and of the 24 MP high risk cases, 18 were high risk by EP (75% agreement). Discrepancies occurred in 14 of 41 cases (34.1%). There was only a weak and non-significant correlation between the MP and EP test with an overall concordance of only 66%. The original therapeutic recommendation was based on the MP and would have been changed in 38% of the patients following EP test results. 4 patients developed distant metastases. The respective tumours of these patients were all classified as high risk by the EP, but only 3 were classified as high risk by the MP.ConclusionBoth tests resulted in different treatment recommendations for a significant proportion of patients and cannot be used interchangeably. The results underscore the urgent need for further comparative analyses of multi-genomic tests to avoid misclassification of disease recurrence risk in breast cancer patients.引言：早期乳腺癌患者的复发风险精准评估，对识别可豁免辅助化疗的患者至关重要。临床实践中，该评估愈发依赖基因表达检测的结果。本研究旨在比较70基因检测试剂盒MammaPrint（MP）与12基因检测试剂盒EndoPredict（EP）的一致性。 方法：本研究选取48例原发性肿瘤的代表性组织，基于常规诊断需求开展MP检测；随后对对应的福尔马林固定石蜡包埋组织实施EP检测，并对两种检测的风险分级结果进行对比。 结果：48例肿瘤中有41例可通过两种检测直接比对。在17例MP判定为低风险的病例中，仅9例被EP判定为低风险（一致率53%）；在24例MP判定为高风险的病例中，18例被EP判定为高风险（一致率75%）。41例病例中存在14例结果不一致（占比34.1%）。MP与EP检测仅存在微弱且无统计学意义的相关性，总体一致率仅为66%。初始治疗建议基于MP检测结果制定，其中38%的患者的治疗方案会因EP检测结果发生变更。共有4例患者发生远处转移，该4例患者的肿瘤均被EP判定为高风险，但其中仅3例被MP判定为高风险。 结论：两种检测对相当比例的患者给出了不同的治疗建议，二者不可互换使用。本研究结果凸显了开展多基因检测对比分析的迫切必要性，以避免乳腺癌患者复发风险的误分类。