Background/Objectives: Colorectal cancer (CRC) is one of the most common human malignancies worldwide. The somatotropin-releasing inhibitory factor/somatostatin (SRIF/SST) acts through activation of five membrane receptors (SSTRs, SST1-5). The diagnostic and prognostic role of these peptides in sporadic CRC remains unclear. This study aimed to determine the role of tissue expression of SST and all SSTRs in the pathogenesis, diagnosis, and prognosis of sporadic CRC. Methods: The expression of SST and all SSTRs was assessed in the tissues of CRC patients, control colorectal mucosa and lymph node metastasis from the same patients using real-time quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry (IHC). Results: Decreased SST (mRNA and peptide) and higher SST2 and SST5 (mRNA and peptide) expression in CRC vs. control was noted. A negative correlation between SST mRNA expression and patient’s age in CRC and control groups were observed. IHC study confirmed the coexpression of SSTRs in all tissue groups and significant dependence on the cellular localization. Immunoexpression of SST2 and SST3 showed the most correlations with clinicopathological data in CRC patients. Interestingly, only control tissue showed differences in SST1-5 expression depending on the colon segment. Conclusions: Reduced SST expression in CRC indicates a weakening in its antitumor effect in this cancer in vivo. Overexpression of SST2 and SST5 in CRC suggests that these receptors play an important role in the pathogenesis of this cancer. Analysis of SST1-5 tissue expression allows for differentiation between the mucinous and nonmucinous CRC subtypes. The coexpression of all SST1-5 and overexpression of not only SST2 and SST5 in CRC may have applications for future therapy based on the SRIF system in sporadic CRC.
背景/目的：结直肠癌是全球最常见的人类恶性肿瘤之一。生长抑素通过激活五种膜受体发挥作用。这些肽类在散发性结直肠癌中的诊断和预后作用尚不明确。本研究旨在探讨生长抑素及其所有受体在散发性结直肠癌组织中的表达，对其发病机制、诊断及预后的意义。方法：采用实时定量聚合酶链反应和免疫组织化学技术，检测结直肠癌患者癌组织、对照结直肠黏膜及同患者淋巴结转移灶中生长抑素及其所有受体的表达情况。结果：与对照组相比，结直肠癌组织中生长抑素表达降低，而生长抑素受体2和5表达升高。在结直肠癌组和对照组中均观察到生长抑素mRNA表达与患者年龄呈负相关。免疫组化研究证实所有受体在各组织组中均有共表达，且其表达显著依赖于细胞定位。生长抑素受体2和3的免疫表达与结直肠癌患者的临床病理资料相关性最强。值得注意的是，仅在对照组织中观察到生长抑素受体1-5的表达因结肠区段不同而存在差异。结论：结直肠癌中生长抑素表达降低，表明其体内抗肿瘤作用在该癌症中减弱。生长抑素受体2和5在结直肠癌中的过表达提示这些受体在该癌症的发病机制中起重要作用。生长抑素受体1-5的组织表达分析可用于区分黏液性和非黏液性结直肠癌亚型。所有生长抑素受体1-5的共表达以及结直肠癌中不仅限于受体2和5的过表达，可能为未来基于生长抑素系统的散发性结直肠癌治疗提供应用前景。
肿瘤(癌症)患者之家