Public Laboratory, Key Laboratory of Breast Cancer Prevention and Therapy, Ministry of Education, National Clinical Research Center for Cancer, Tianjin Medical University Cancer Institute and Hospital; Tianjin Medical University, Tianjin, China.
Center for Personalized Diagnostics, Biodesign Institute, Arizona State University, Tempe, AZ, USA.
Mod Pathol. 2017 Nov;30(11):1516-1526. doi: 10.1038/modpathol.2017.86. Epub 2017 Jul 28.
The amplification of chromosome 9p24.1 encoding PD-L1, PD-L2, and JAK2 has been reported in multiple types of cancer and is associated with poor outcome, upregulation of PD-L1, and activation of the JAK/STAT pathway. We have developed a novel fluorescence in situ hybridization assay which combines 3 probes mapping to 9p24.1 with a commercial chromosome 9 centromere (CEN9) probe for detection of the JAK2/9p24.1 amplification. JAK2 fluorescence in situ hybridization was compared with array-based comparative genomic hybridization in 34 samples of triple negative breast cancer tumor. By array-based comparative genomic hybridization, 15 had 9p24.1 copy-number gain (logratio>0.3) and 19 were classified as non-gain (logratio≤0.3). Copy-number gain was defined as JAK2/CEN9 ratio ≥1.1 or average JAK2 signals≥3.0. Twelve of 15 samples with copy-number gain by array-based comparative genomic hybridization were also detected by fluorescence in situ hybridization. Eighteen of 19 samples classified as copy-number non-gain by array-based comparative genomic hybridization were concordant by array-based comparative genomic hybridization. The sensitivity and specificity of the fluorescence in situ hybridization assay was 80% and 95%, respectively (P=0.02). The sample with the highest level of amplification by array-based comparative genomic hybridization (logratio=3.6) also scored highest by fluorescence in situ hybridization (ratio=8.2). There was a correlation between the expression of JAK2 and amplification status (Mean 633 vs 393, P=0.02), and there was a trend of association with PD-L1 RNA expression (Mean 46 vs 22, P=0.11). No significant association was observed between PD-L1 immunohistochemistry expression and copy-number gain status. In summary, the novel array-based comparative genomic hybridization assay for detection of chromosome 9p24.1 strongly correlates with the detection of copy-number gain by array-based comparative genomic hybridization. In triple negative breast cancer, this biomarker may identify a relevant subset of patients for targeted molecular therapies.
9p24.1 染色体编码 PD-L1、PD-L2 和 JAK2 的扩增已在多种类型的癌症中报道，并与不良预后、PD-L1 的上调和 JAK/STAT 通路的激活相关。我们开发了一种新的荧光原位杂交检测方法，该方法结合了 3 个针对 9p24.1 的探针和一个商业性的染色体 9 着丝粒（CEN9）探针，用于检测 JAK2/9p24.1 扩增。在 34 例三阴性乳腺癌肿瘤样本中，比较了 JAK2 荧光原位杂交和基于阵列的比较基因组杂交。通过基于阵列的比较基因组杂交，15 例具有 9p24.1 拷贝数增益（logratio>0.3），19 例被归类为非增益（logratio≤0.3）。拷贝数增益定义为 JAK2/CEN9 比值≥1.1 或平均 JAK2 信号≥3.0。通过基于阵列的比较基因组杂交检测到的 15 个具有拷贝数增益的样本中有 12 个也通过荧光原位杂交检测到。通过基于阵列的比较基因组杂交归类为拷贝数非增益的 19 个样本中有 18 个通过基于阵列的比较基因组杂交检测结果一致。荧光原位杂交检测的灵敏度和特异性分别为 80%和 95%（P=0.02）。通过基于阵列的比较基因组杂交检测到的拷贝数增益最高的样本（logratio=3.6），其荧光原位杂交检测结果也最高（比值=8.2）。JAK2 的表达与扩增状态之间存在相关性（平均值 633 与 393，P=0.02），并且与 PD-L1 RNA 表达呈趋势相关（平均值 46 与 22，P=0.11）。PD-L1 免疫组化表达与拷贝数增益状态之间无显著相关性。总之，用于检测 9p24.1 的新型基于阵列的比较基因组杂交检测方法与基于阵列的比较基因组杂交检测到的拷贝数增益具有很强的相关性。在三阴性乳腺癌中，这种生物标志物可能可以识别出相关的分子靶向治疗亚群。
