We hypothesise that the NRF2 transcription factor would act a biomarker of poor prognosis in colorectal cancer. We derived and validated an mRNA based metagene signature of NRF2 signalling and validated it in 1360 patients from 4 different datasets as an independent biomarker of poor prognosis. This is a novel insight into the molecular signalling of colorectal cancer.

Background: NRF2 over activity confers poor prognosis in some cancers but its prognostic role in colorectal cancer (CRC) is unknown. As a transcription factor, we hypothesise a signature of NRF2 regulated genes could act as a prognostic biomarker in CRC and reveal novel biological insights.

Methods: Using known NRF2 regulated genes, differentially expressed in CRC, we defined a signature of NRF2 pathway activity using principal component analysis and Cox proportional hazard models and tested it in four independent mRNA datasets, profiled on three different mRNA platforms.

Results: 36 genes comprised the final NRF2 signature. 1360 patients were included in the validation. High NRF2 was associated with worse disease free survival (DFS) and/or overall survival (OS) in all datasets: (GSE14333 HR=1.55, 95% C.I 1.2–2.004, p = 0.0008; GSE39582 HR=1.24, 95% C.I 1.086–1.416, p = 0.001; GSE87211 HR=1.431, 95% C.I 1.06–1.93, p = 0.056; MRC FOCUS trial HR=1.14, 95% C.I 1.04–1.26, p = 0.008). In multivariate analyses, NRF2 remained significant when adjusted for stage and adjuvant chemotherapy in stage I-III disease, and BRAF V600E mutation and sidedness in stage IV disease. NRF2 activity was particularly enriched in Consensus Molecular Subtype (CMS) 4.

Conclusion: For the first time, NRF2 is shown to be a consistent, robust prognostic biomarker across all stages of colorectal cancer with additional clinical value to current known prognostic biomarkers. High NRF2 signalling in CMS 4 further refines the molecular taxonomy of CRC, a new biological insight, suggesting avenues of further study.

我们假设 NRF2 转录因子将作为结直肠癌预后不良的生物标志物。我们衍生并验证了基于 mRNA 的 NRF2 信号元基因特征，并在来自 4 个不同数据集的 1360 名患者中将其验证为预后不良的独立生物标志物。这是对结直肠癌分子信号传导的新见解。

背景： NRF2 过度活跃会导致某些癌症预后不良，但其在结直肠癌 (CRC) 中的预后作用尚不清楚。作为转录因子，我们假设 NRF2 调节基因的特征可以作为 CRC 的预后生物标志物并揭示新的生物学见解。

方法：使用已知的 NRF2 调节基因，在 CRC 中差异表达，我们使用主成分分析和 Cox 比例风险模型定义了 NRF2 途径活性的特征，并在四个独立的 mRNA 数据集中对其进行了测试，在三个不同的 mRNA 平台上进行了分析。

结果： 36 个基因构成了最终的 NRF2 特征。1360 名患者被纳入验证。在所有数据集中，高 NRF2 与较差的无病生存期 (DFS) 和/或总生存期 (OS) 相关：(GSE14333 HR=1.55, 95% CI 1.2–2.004, p  = 0.0008; GSE39582 HR=1.24, 95% CI 1.086 –1.416，p  = 0.001；GSE87211 HR=1.431，95% CI 1.06–1.93，p  = 0.056；MRC FOCUS 试验 HR=1.14，95% CI 1.04–1.26，p  = 0.008）。在多变量分析中，当调整 I-III 期疾病的分期和辅助化疗，以及 BRAF V600E 突变和 IV 期疾病的偏侧性时，NRF2 仍然显着。NRF2 活性在共识分子亚型 (CMS) 4 中特别丰富。

结论： NRF2 首次被证明在结直肠癌的所有阶段都是一致的、稳健的预后生物标志物，与目前已知的预后生物标志物相比具有额外的临床价值。CMS 4 中的高 NRF2 信号进一步完善了 CRC 的分子分类，这是一种新的生物学见解，为进一步研究提供了途径。