腫瘤浸潤T淋巴球其表現FOXP3次群的比例隨子宮頸癌的嚴重度增加

Abstract

子宮頸癌的形成是經由一連串上皮細胞病變的癌前兆所轉變而來，這一系列子宮頸上皮內的異常增生，稱為子宮頸上皮內贅瘤。 先前的研究發現存在於子宮頸癌之腫瘤浸潤淋巴球次群發生改變而且無法執行其正常的免疫功能。 癌症病人之免疫系統異常的原因有很多，其中包含了具有抑制性功能之調節性Ｔ淋巴球，其數量發生改變所造成。FOXP3向來被認定為主要控制CD4+CD25+調節性Ｔ淋巴球次群之發育和功能上最主要的基因。本論文中，首先針對腫瘤浸潤淋巴球在子宮頸癌的分佈做探討，結果顯示了腫瘤浸潤淋巴球的分布主要位於腫瘤周圍，而不是浸潤入整個腫瘤。進一步分析腫瘤浸潤淋巴球的特徵發現，表現FOXP3之淋巴球次群其主要細胞型為CD4+CD25+。 為了探討調節性Ｔ淋巴球在子宮頸癌的進展及惡化上所扮演的可能角色，我們利用比較不同時期之子宮頸病變其表現FOXP3+ 細胞次群在T淋巴球中所佔的比例，來推論在腫瘤生長的過程中 ，調節性Ｔ淋巴球是否參與在抑制免疫反應的角色。 利用免疫螢光染色的方法， 使用共軛焦顯微鏡來做觀察，再透過影像軟體的計算，來對表現FOXP3蛋白的細胞作量化。得到的結果顯示在越後期的子宮頸癌病人，其T淋巴球中表現FOXP3+次群的比例就越高。此外，此群細胞可分泌Granzyme B蛋白，推測可能經由Granzyme B蛋白的分泌來執行其調節性T淋巴球之免疫抑制功能。研究結果顯示，在不同時期之子宮頸病變其表現FOXP3+ 細胞次群顯著的差異下，表示調節性Ｔ淋巴球在子宮頸癌的惡化上可能佔有極重要的角色。

Cervical cancer (CC) is preceded by well-defined precancerous changes in the epithelium known as cervical intraepithelial neoplasm (CIN). Our previous studies have revealed that the subpopulations and functions of tumor- infiltrating lymphocytes (TIL) from CC are altered. Dysfunction of the host immune system in cancer patients can be due to a number of reasons including the inhibitory functions of regulatory T (Treg) cells. FOXP3 has been shown to be a master control gene for the development and function of CD4+CD25+ Treg cells. In the present study, I first focused on the distribution of TILs in cervical cancer tissues and cervical intraepithelial neoplasm. The data showed that TILs located around the tumor cells and barely presence inside the tumor. Next, I characterized the phenotype of FOXP3+ T cells. By using the double-staining analysis, the CD4+CD25+FOXP3+ phenotype of tumor-associated Treg cells have accumulated around the tumor cells. To characterize the pathophysiological role of Treg cells in the progression of CC, I compared samples from four groups: CIN I/II, CIN III, CC with and without lymph node metastasis. By using the immunofluorescence staining and confocal-based image quantitative analysis in paraffin-embedded tissue sections, excess in the presence of FOXP3+ cells is observed from CC compared to that from CIN. Moreover, these FOXP3+ cells can express Granzyme B, indicated that Granzyme B secretion might involved in the inhibitory function of Treg cells. The significant increase in these CD4+CD25+FOXP3+ cells in CC indicates that Treg might play an important role in the progression of CC.