Aims and experimental design. The acute-phase protein haptoglobin (Hp) has been recently detected in colorectal cancer (CRC) tissue, where its expression correlates with metastasis. Recently, we identified Hp as a CDw75 antigen-expressing protein in colorectal tissue. To deepen the knowledge of this protein in CRC, we studied the expression of Hp in healthy and tumour tissue specimens from 62 CRC patients by immunohistochemistry and Western blotting, as well as in the Caco-2 and HT-29 CRC cell lines by quantitative PCR, immunofluorescence microscopy and flow cytometry. Results and discussion. Hp immuno-positive staining was absent in the 18 healthy colorectal specimens analysed, whereas it was observed in 24% (15/62) of the tumour specimens as cytoplasmic granules within cancer cells. Furthermore, Hp expression in CRC was associated with Dukes' stage and the presence of metastasis in our population of study. In vitro cultured Caco-2 and HT-29 cells expressed mRNA for Hp and the protein was detected at the cell surface. Conclusions. This study confirms the expression of Hp in CRC, both in vivo and in vitro, and provides further evidence of its association with disease progression and metastasis.

中文翻译：

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人大肠癌中肝珠蛋白的表达。

目的和实验设计。最近在结直肠癌（CRC）组织中检测到了急性期蛋白触珠蛋白（Hp），其表达与转移相关。最近，我们确定Hp是结直肠组织中CDw75抗原表达蛋白。为了加深对该蛋白在CRC中的了解，我们通过免疫组织化学和蛋白质印迹研究了62名CRC患者健康和肿瘤组织标本中Hp的表达，并通过定量PCR研究了Hp在Caco-2和HT-29 CRC细胞系中的表达，免疫荧光显微镜和流式细胞仪。结果与讨论。分析的18个健康结直肠标本中没有进行Hp免疫阳性染色，而在肿瘤标本中有24％（15/62）在癌细胞中观察到了Hp免疫染色。此外，CRC中的Hp表达与Dukes's相关。研究人群中的转移阶段和转移的存在。体外培养的Caco-2和HT-29细胞表达Hp mRNA，并在细胞表面检测到该蛋白。结论。这项研究证实了Hp在CRC中的体内和体外表达，并提供了其与疾病进展和转移相关的进一步证据。