Background: Appropriate immunohistochemistry (IHC) scoring criteria can guarantee the reliability of mutation detection results. Most current studies suggest that the "four-grade criterion" may be the best among all scoring systems. The aim of this study is to discuss the influence of different four-grade immunohistochemistry scoring criteria on the test results.
Methods: Three different four-grade immunohistochemistry scoring criteria were respectively used to evaluate the EGFR status of 83 cases of non-small cell of lung cancer (NSCLC) samples. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), the agreement of each criterion compared with the gold standard, and whether statistical significance exists between each criterion were calculated.
Results: No statistical difference was found among the three criteria in detecting EGFR mutations. All three criteria exhibit considerably better specificity than sensitivity. For samples with scores of "3+", PPV could reach up to 100%.
Conclusions: No definite best criterion is among different four-grade scoring criteria. Regardless of the kind of criterion used, the specificity of IHC method in detecting EGFR mutations is markedly better than the sensitivity. For samples with scores of "3+", mutation status can be confirmed, and samples can receive EGFR-TKI therapy directly.
背景与目的 恰当的免疫组化染色评分可确保突变检测结果的可靠性，目前大多数研究认为“四分法”是所有评分系统中最佳的方法。本研究旨在探讨不同四分法染色评分对检测结果的影响。方法 用三种不同的四分法免疫组化染色评分标准评价83例非小细胞肺癌标本表皮生长因子受体（epidermal growth factor receptor, EGFR）突变情况，并以液相芯片法作为金标准进行比较，计算每种方法的灵敏度、特异度、阳性预测值（positive predictive value, PPV）、阴性预测值（negative predictive value, NPV）、与金标准间一致度及三种标准间是否存在统计学差异。结果 三种标准在检测EGFR突变方面不存在统计学差异，每种标准检测结果的特异度均明显优于灵敏度。染色为“3+”的标本，PPV均可高达100%。结论 不同的四分法评分没有绝对的最佳标准，但无论用何种标准，免疫组化法（immunohistochemistry, IHC）检测EGFR突变的特异度均明显优于灵敏度。评分为“3+”的标本，可认为实际确实存在突变，直接接受EGFR酪氨酸激酶抑制剂（tyrosine kinase inhibitor, TKI）治疗。.