Li Xianzhe, Xie Minghao, Yin Shi, Xiong Zhizhong, Mao Chaobin, Zhang Fengxiang, Chen Huaxian, Jin Longyang, Lan Ping, Lian Lei
Department of Colorectal Surgery, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, Guangdong Institute of Gastroenterology, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
Front Genet. 2021 May 4;12:666003. doi: 10.3389/fgene.2021.666003. eCollection 2021.
Immune-related genes (IRGs) play important roles in the tumor immune microenvironment and can affect the prognosis of cancer. This study aimed to construct a novel IRG signature for prognostic evaluation of stage II colorectal cancer (CRC).
Gene expression profiles and clinical data for stage II CRC patients were collected from the Cancer Genome Atlas and Gene Expression Omnibus database. Univariate, multivariate Cox regression, and least absolute shrinkage and selection operator regression were used to develop the IRG signature, namely IRGCRCII. A nomogram was constructed, and the "Cell Type Identification by Estimating Relative Subsets of RNA Transcripts" (CIBERSORT) method was used to estimate immune cell infiltration. The expression levels of genes and proteins were validated by qRT-PCR and immunohistochemistry in 30 pairs of primary stage II CRC and matched normal tissues.
A total of 466 patients with stage II CRC were included, and 274 differentially expressed IRGs were identified. Six differentially expressed IRGs were detected and used to construct the IRGCRCII signature, which could significantly stratify patients into high-risk and low-risk groups in terms of disease-free survival in three cohorts: training, test, and external validation (GSE39582). Receiver operating characteristics analysis revealed that the area under the curves of the IRGCRCII signature were significantly greater than those of the OncotypeDX colon signature at 1 (0.759 vs. 0.623), 3 (0.875 vs. 0.629), and 5 years (0.906 vs. 0.698) disease-free survival, respectively. The nomogram performed well in the concordance index (0.779) and calibration curves. The high-risk group had a significantly higher percentage of infiltrated immune cells (e.g., M2 macrophages, plasma cells, resting mast cells) than the low-risk group. Finally, the results of qRT-PCR and immunohistochemistry experiments performed on 30 pairs of clinical specimens were consistent with bioinformatics analysis.
This study developed and validated a novel immune prognostic signature based on six differentially expressed IRGs for predicting disease-free survival and immune status in patients with stage II CRC, which may reflect immune dysregulation in the tumor immune microenvironment.
免疫相关基因（IRGs）在肿瘤免疫微环境中发挥重要作用，并可影响癌症预后。本研究旨在构建一种用于评估II期结直肠癌（CRC）预后的新型IRG特征。
从癌症基因组图谱和基因表达综合数据库收集II期CRC患者的基因表达谱和临床数据。采用单变量、多变量Cox回归以及最小绝对收缩和选择算子回归来开发IRG特征，即IRGCRCII。构建了列线图，并使用“通过估计RNA转录本相对子集进行细胞类型鉴定”（CIBERSORT）方法来估计免疫细胞浸润。通过qRT-PCR和免疫组化在30对原发性II期CRC及配对的正常组织中验证基因和蛋白质的表达水平。
共纳入466例II期CRC患者，鉴定出274个差异表达的IRGs。检测到6个差异表达的IRGs并用于构建IRGCRCII特征，该特征可在训练、测试和外部验证（GSE39582）三个队列中根据无病生存期将患者显著分层为高风险和低风险组。受试者工作特征分析显示，在1年（0.759对0.623）、3年（0.875对0.629）和5年（0.906对0.698）无病生存期时，IRGCRCII特征的曲线下面积显著大于OncotypeDX结肠特征。列线图在一致性指数（0.779）和校准曲线方面表现良好。高风险组浸润免疫细胞（如M2巨噬细胞、浆细胞、静息肥大细胞）的百分比显著高于低风险组。最后，对30对临床标本进行的qRT-PCR和免疫组化实验结果与生物信息学分析一致。
本研究开发并验证了一种基于6个差异表达IRGs的新型免疫预后特征，用于预测II期CRC患者的无病生存期和免疫状态，这可能反映了肿瘤免疫微环境中的免疫失调。
