Manchester Cytology Centre, Manchester University NHS Foundation Trust, Manchester, UK.
Genomic Diagnostics Laboratory, Manchester University NHS Foundation Trust, Manchester, UK.
Cytopathology. 2021 Sep;32(5):621-630. doi: 10.1111/cyt.12994. Epub 2021 Jun 15.
Rearranged ROS1, present in 1%-2% of non-small cell lung cancer (NSCLC) patients, usually young, never or light smokers, is assessed by fluorescence in situ hybridization (FISH) to determine eligibility for tyrosine kinase inhibitors (TKI). Immunohistochemistry (IHC) for the protein product of ROS1 rearrangement, a cost-effective alternative, is validated on cytology and small biopsy samples.
From 1 March to 31 December 2019, cytology cell blocks and small biopsy samples from a selected cohort of NSCLC patients were concurrently tested for ROS1 gene rearrangement by Vysis 6q22 Break Apart FISH probe and IHC using Cell Signalling D4D6 antibody. Mismatch cases were tested by an RNA fusion next generation sequencing (NGS) panel.
In a prospective population of 95 cases, 91 were negative and two were positive by both FISH and IHC. Both dual positive cases were female never smokers and benefited from TKI treatment. Another two cases were positive by FISH but negative by IHC and repeat by NGS showed one to be negative but one failed. Turnaround time for IHC was 0 to 8 days from request to authorisation, whilst that of FISH was 9 to 42 days at a cost of £51 and £159 respectively.
IHC to assess for the protein product of ROS1 gene rearrangement on cytology cell blocks and small biopsy samples in a routine setting is a promising screening method to assess eligibility for TKI treatment with positive and indeterminate cases confirmed by FISH or NGS as it has good negative predictive value, faster turnaround time and is cost effective, with proven technical and clinical validation.
ROS1 重排存在于 1%-2%的非小细胞肺癌（NSCLC）患者中，这些患者通常为年轻、从不或轻度吸烟的人群，通过荧光原位杂交（FISH）评估其是否适合接受酪氨酸激酶抑制剂（TKI）治疗。ROS1 重排蛋白产物的免疫组织化学（IHC）检测是一种具有成本效益的替代方法，已在细胞学和小活检样本中得到验证。
2019 年 3 月 1 日至 12 月 31 日，对选定的 NSCLC 患者的细胞学细胞块和小活检样本同时进行 Vysis 6q22 Break Apart FISH 探针检测和使用 Cell Signalling D4D6 抗体的 IHC 检测，以评估 ROS1 基因重排情况。对不匹配的病例进行 RNA 融合下一代测序（NGS）面板检测。
在一项前瞻性的 95 例人群研究中，91 例为阴性，2 例同时通过 FISH 和 IHC 检测呈阳性。这两个双阳性病例均为女性、从不吸烟且受益于 TKI 治疗。另外两个病例 FISH 检测阳性而 IHC 检测阴性，重复 NGS 检测显示一个病例为阴性，一个病例失败。从申请到授权，IHC 的周转时间为 0 至 8 天，而 FISH 的周转时间为 9 至 42 天，费用分别为 51 英镑和 159 英镑。
在常规环境下，使用 IHC 检测细胞学细胞块和小活检样本中 ROS1 基因重排的蛋白产物，是一种有前途的筛选方法，可评估 TKI 治疗的适应证，阳性和不确定病例通过 FISH 或 NGS 确认，因为它具有良好的阴性预测值、更快的周转时间和成本效益，且具有经过验证的技术和临床验证。
