Expression of chemokines in gastrointestinal cancer

背景。近年来，研究表明一些癌前组织和恶性肿瘤以及培养的癌细胞系能够分泌趋化因子。巨噬细胞炎症蛋白-1 β(MIP-β)属于C-C趋化因子家族，涉及广泛的炎症过程。然而，MIP-β如何影响肿瘤生长尚不清楚。利用MIP-1β特异性单克隆抗体，应用免疫组化技术检测MIP-1β在手术切除的胃癌组织中的表达，并比较MIP-1β在不同组织学组织中的表达规律。在34.6%的分化癌中检测到MIP-1β的弱染色，但其在每个细胞中的染色强度低于正常上皮。未分化癌呈实型和弥漫型对比染色。MIP-β在所有实体型未分化癌中完全不存在。相比之下，MIP-1β在68%的非实体型低分化癌和83%的印戒细胞癌样本中强烈表达。特别是，MIP-1β在侵袭性病变前部的癌细胞中被强烈染色。在任何病理类型中，MIP-1β的表达水平与癌组织中单个核细胞浸润程度无显著相关性。我们的研究结果表明，胃上皮中MIP-1β的产生可能与胃癌的发生或进展有关，尽管它似乎在癌组织中免疫细胞的募集中没有发挥主要作用。特别是MIP-1β可能参与了未分化表型胃癌细胞的侵袭步骤。

Background. Recently, it has been shown that some precancerous tissues and malignant tumors as well as cultured cancer cell lines are capable of secreting chemokines. Macrophage inflammatory protein-1 β(MIP-β) belongs to the C-C chemokine family that is implicated in a wide range of inflammatory processes. However, how the MIP-β affect tumor growth is unknown.Method. With the specific mAb to MIP-1β, we examined the expression of MIP-1β in surgically resected gastric carcinomas using immunohistochemistry, and compared the expression pattern in various carcinomas with different histology.Result. Weak staining of MIP-1β was detected in 34.6% of differentiated carcinomas, but their staining intensity in each cell was less prominent than in normal epithelium. Undifferentiated carcinomas showed contrasted staining pattern between solid type and diffuse type. MIP-β was completely absent in all the undifferentiated carcinoma with solid type growth pattern. In contrast, MIP-1β was strongly expressed in 68% of non-solid type of poorly differentiated carcinoma and 83% of signet-ring cell carcinoma samples. In particular, MIP-1β was strongly stained in carcinoma cells at the front of invasive lesions. In any pathological types, the expression level of MIP-1β did not have a significant correlation with the degree of mononuclear cell infiltration in cancer tissue.Conclusion. Our results suggest the possibility that MIP-1β production in gastric epithelium may be related to the development or progression of gastric cancer, although it does not seem to play a major role in the recruitment of immune cells in cancer tissue. Especially, MIP-1β may contribute to the invasion step of gastric carcinoma cells with undifferentiated phenotype.