Interleukin-17 (IL-17) is a pro-inflammatory cytokine found in various cancers. Current evidence indicates that IL-17 plays a vital role in tumour initiation and progression in colorectal carcinoma (CRC) via binding with its receptor, IL-17RA. However, the association between clinicopathological features and presence of IL-17 and IL-17RA protein in primary CRC tissues remains unclear. This study also investigates the difference between the presence of IL-17 and IL-17RA in the paired tumour tissues versus adjacent normal tissues. The presence of IL-17RA and IL-17 protein in primary CRC tissues was determined by immunohistochemistry. Associations between clinicopathological features and IL-17RA and IL-17 immunoreactivity, were analyzed by χ2 tests. We found that both IL-17RA (p = 0.001) and IL-17 (p = 0.025) in tumour cells of primary CRC tissues was significantly lower as compared to adjacent normal tissue. Positive immunoreactivity for IL-17RA and IL-17 were detected in 51.0% and 16.8% of tumour tissues, respectively. Furthermore, negative immunoreactivity of IL-17R was significantly associated with advanced stage according to TNM classifier (p = 0.027), high grade of tumour (p = 0.019), increased depth of tumour invasion (p = 0.023) and vascular invasion (p = 0.039). Positive IL-17 immunoreactivity was associated with advanced stage (p = 0.008) and lymph node metastasis (p = 0.008). Thus, this study suggests that the loss of IL-17RA expression occurs as tumour progresses and this may predict the aggressiveness of tumour whilst expression of IL-17 promotes tumour progression and lymph node metastasis. Thus, loss of IL-17RA could be a useful prognostic biomarker for tumour progression in CRC patients.

白介素17（IL-17）是在多种癌症中发现的促炎细胞因子。当前证据表明，IL-17通过与受体IL-17RA结合，在结直肠癌（CRC）的肿瘤发生和发展中起着至关重要的作用。然而，临床病理特征与原发性CRC组织中IL-17和IL-17RA蛋白的存在之间的关联仍不清楚。这项研究还研究了成对的肿瘤组织与相邻正常组织中IL-17和IL-17RA的存在差异。通过免疫组织化学确定原发性CRC组织中IL-17RA和IL-17蛋白的存在。通过χ2检验分析临床病理特征与IL-17RA和IL-17免疫反应性之间的关联。我们发现IL-17RA（p  = 0.001）和IL-17（p = 0.025）与邻近的正常组织相比，原发性CRC组织的肿瘤细胞中的肿瘤细胞显着降低。IL-17RA和IL-17的阳性免疫反应性分别在51.0％和16.8％的肿瘤组织中检测到。此外，根据TNM分类器，IL-17R的阴性免疫反应与晚期阶段（p  = 0.027），高级别肿瘤（p  = 0.019），肿瘤浸润深度（p  = 0.023）和血管浸润（p  = 0.039）。IL-17阳性免疫反应与晚期（p  = 0.008）和淋巴结转移（p = 0.008）。因此，该研究表明IL-17RA表达的丧失随着肿瘤的进展而发生，并且这可以预测肿瘤的侵袭性，而IL-17的表达促进肿瘤的进展和淋巴结转移。因此，IL-17RA的丢失可能是CRC患者肿瘤进展的有用的预后生物标志物。