Prognostic significance of Fas and Fas ligand expressions in human esophageal cancer.

Esophageal carcinomas have recently been shown to express Fas ligand (FasL) and down-regulate Fas to escape from host immune surveillance. However, the prognostic importance of Fas/FasL and their correlation with clinicopathological characteristics are yet to be delineated in this highly malignant carcinoma. Specimens from 106 esophageal squamous cell carcinoma patients were used for immunohistochemical evaluation of Fas, FasL, and CD8 expressions. Fifty-two (49%) and 34 (32%) patients were positive for FasL and Fas, respectively. There were no associations between FasL expression and clinicopathological characteristics except lymph vessel invasion. Strong FasL expression correlated with significant (P = 0.0011) decrease in tumor nest CD8+ cells. However, neither FasL nor CD8+ had any impact on patient survival. Strong Fas expression was correlated with depth of invasion (40.3% in pT1,T2 versus 20.5% in pT3,T4; P = 0.0308), histological differentiation (45.7% in well versus 25.4% in nonwell; P = 0.0347), and lymph node metastasis (22.6% in positive versus 45.5% in negative; P = 0.0129). Fas expression was one of the independent favorable prognosticators for patients' survival (risk ratio, 3.26; P = 0.0103) in esophageal SCC. Fas expression was an independent prognosticator for recurrence-free survival, whereas FasL expression did not influence the survival in esophageal squamous cell carcinoma. Down-regulation of tumor Fas may be the hallmark of immune privilege for the tumor, thus causing the patients' poorer outcome. Tumor FasL may counterattack the host immune cells to such an extent that the prognosis is not affected.     

Fas ligand expression is correlated with metastasis in colorectal carcinoma

The Fas/Fas ligand (FasL) system is one apoptotic pathway through which malignant tumors can evade immune surveillance. While FasL is expressed in malignant tumors, Fas is conversely downregulated to escape host immune attack, resulting in tumor invasion. The aim of the current study was to find out further clinicopathological significance of FasL expression in carcinoma of the colon and rectum. FasL expression was investigated using immunohistochemical staining in 143 consecutive patients with primary colorectal carcinomas. Seventy-nine carcinomas (55.2%) expressed FasL. The incidence of lymph node and distant metastases in carcinomas expressing FasL was significantly higher than in carcinomas that did not express FasL (p = 0.031 and p = 0.0003, respectively). Although univariate analysis showed that survival in patients with carcinomas expressing FasL was significantly poorer than that in patients with carcinomas without FasL expression (p = 0.001), only Dukes' stage was an independent prognosticator by multivariate analysis. FasL expression was found to be correlated with lymph node involvement and distant metastases in colorectal carcinoma.     

大肠癌中Fas、FasL、FAP-1的表达及意义

目的:研究大肠癌组织中Fas、FasL及FAP-1的表达状况及临床意义。方法:用Fas、FasL多克隆抗体及FAP-1单克隆抗体对42例大肠癌组织标本进行免疫组化染色,检测其Fas、FasL及FAP-1的蛋白表达,并以相应的切缘正常大肠组织作对照。结果:大肠癌组织中Fas表达(36％)显著低于正常大肠黏膜上皮(60％)(P<0.05),且粘液腺癌及印戒细胞癌Fas表达率显著低于管状、乳头状腺癌(P<0.05),另外,正常大肠粘膜固有层的淋巴细胞及浸润肿瘤的淋巴细胞可见Fas表达;正常的大肠粘膜上皮表达FasL(40％),恶变后的大肠粘膜FasL表达上调(71％),两者表达率有显著性差异(P<0.05),且溃疡型及浸润型大肠癌较隆起型表达率高(P<0.05),浸润至正常大肠粘膜及肿瘤的淋巴细胞未见或偶见FasL表达;大肠癌细胞无论其Fas表达高低都未见FAP-1表达。结论:大肠癌细胞通过Fas表达下调和(或)FasL表达上调以实现其免疫逃避,Fas、FasL的表达状况与肿瘤病理类型有关,粘液腺癌及印戒细胞癌、溃疡型及浸润型大肠癌的恶性程度高、预后差可能与其Fas、FasL的表达异常有关;FAP-1在大肠癌免疫逃避中可能不起重要作用。     

Fas ligand expression in metastatic renal cell carcinoma during interleukin-2 based immunotherapy: no in vivo effect of Fas ligand tumor counterattack.

PURPOSE: It has been hypothesized that tumor cells expressing Fas ligand (FasL) might be able to counterattack and neutralize tumor-infiltrating lymphocytes. We assessed the effect of FasL tumor counterattack on the clinical outcome of interleukin-2 (IL-2)-based immunotherapy in metastatic renal cell carcinoma. EXPERIMENTAL DESIGN: Tumor core needle biopsies were obtained before IL-2-based immunotherapy in 86 patients and repeated within the first cycle in 57 patients. Tumor cells expressing FasL and intratumoral lymphocyte subsets expressing CD4, CD8, CD56, and CD57 were analyzed by immunohistochemistry. RESULTS: At baseline, negative FasL staining in tumor cells was seen in 10 of 86 (12%) biopsies, whereas intense FasL staining was seen (a) in fewer than 10% of tumor cells in 26 (30%) biopsies; (b) in 11 to 50% of tumor cells in 25 (29%) biopsies; (c) in 51 to 90% of tumor cells in 18 (21%) biopsies; and (d) in >90% of tumor cells in 7 (8%) biopsies. On treatment, tumor FasL expression did not change from baseline levels. Moreover, tumor FasL expression was not correlated with objective response or survival whereas the absolute number of CD4(+), CD8(+), CD56(+), and CD57(+) cells per mm(2) tumor tissue at baseline was significantly higher in responding patients compared with nonresponding patients (P = 0.01, P = 0.008, P = 0.015, and P < 0.001, respectively). During the first course of immunotherapy, the absolute number of CD4(+), CD8(+), and CD57(+) cells per mm(2) tumor tissue was significantly higher in responding patients compared with nonresponding patients (P = 0.034, P < 0.001, and P < 0.001, respectively). However, no correlation was observed between the number of intratumoral lymphocytes and tumor FasL expression level. CONCLUSION: These observations do not support the hypothesis that FasL tumor "counterattack" has an effect on the clinical outcome in metastatic renal cell carcinoma during IL-2-based immunotherapy.     

Expression of Fas ligand is an early event in colorectal carcinogenesis

BACKGROUND AND OBJECTIVES: Fas ligand (FasL) is expressed in many cancers and plays an important role in establishing immunologically privileged environments that allow tumors to escape the host's immune surveillance. We investigate the expression of FasL in human colorectal cancer and colorectal adenoma and elucidate the relationship between FasL expression and the clinicopathological characteristics of colorectal cancers. METHODS: We examined 214 colorectal cancer specimens and 83 colorectal adenoma specimens. Expression of FasL was determined by immunohistochemical staining using a specific monoclonal antibody. We analyzed the relationship between the results of FasL expression and clinicopathological data statistically. RESULTS: FasL expression was detected in 173 (80.8%) of 214 colorectal carcinomas and 34 (40.9%) of 83 colorectal adenomas. The status of FasL expression in colorectal carcinoma was independent of clinicopathological features including tumor stage, histologic grade, lymphatic invasion, venous invasion, lymph node metastasis, liver metastasis, and Dukes stage. In colorectal adenoma, FasL expression was more frequently observed in high-grade atypia than in low-grade atypia (P = 0.05). CONCLUSIONS: FasL expression is commonly observed not only in cancer but also in highly dysplastic tissue. These observations suggest that FasL expression may be an important event in the transformation process leading to adenocarcinoma.     

FasL在食管癌中的表达—一种免疫反攻击机制

目的：研究食管癌细胞Ｆａｓ配体的表达情况及其与食管癌发生和预后间的关系。方法：用免疫组化法,检测了４０例食管癌原发灶和１７例淋巴结转移灶中ＦａｓＬ在食管癌细胞及肿瘤浸润淋巴细胞中的表达情况。结果：３４例（８５％）原发性食管癌细胞中均有不同程度的ＦａｓＬ的表达,３１例（８２．５％）ＴｉＬ细胞ＦａｓＬ亦表达阳性,１７例淋巴结转移灶癌细胞中,ＦａｓＬ均强阳性表达。结论：食管癌细胞可能通过ＦａｓＬdisplay     

Fas (CD95/APO-1) and Fas ligand expression in normal pancreas and pancreatic tumors. Implications for immune privilege and immune escape

BACKGROUND: Fas (CD95/APO-1) and Fas ligand (FasL) play key roles in immunologic homeostasis and immune privilege and may regulate normal cell turnover. Earlier studies had suggested that FasL-positive pancreatic carcinoma cell lines can induce apoptosis in T cells, thereby evading host immune surveillance. In the current study the authors have characterized the expression of Fas and FasL in the normal pancreas and in pancreatic neoplasia. METHODS: Pancreatic resection specimens with ductal-type adenocarcinoma or intraductal dysplasia (n = 41), nonductal pancreatic neoplasms (n = 5), and chronic pancreatitis (n = 4) were examined for Fas and FasL expression by immunohistochemistry. The results in invasive adenocarcinoma were compared to those for benign ducts and intraductal dysplasia, and correlated with clinicopathologic features of the tumors and with patient survival. RESULTS: Fas was expressed in the normal pancreatic ducts and in intraductal dysplasia in a mixed membrane/cytoplasmic pattern. In all cases of invasive ductal-type adenocarcinoma, membranous Fas could not be detected; cytoplasmic Fas staining was reduced or completely lost. Loss of Fas expression in pancreatic ductal-type adenocarcinomas significantly correlated with poorer differentiation and extrapancreatic spread of the tumors and was associated with a shorter overall survival. FasL expression was present in the normal pancreatic ducts as well as in islet cells and was maintained in all pancreatic tumors. CONCLUSIONS: These results implicate the Fas pathway in the regulation of physiologic cell turnover and immune privilege in the normal pancreas and indicate that loss of Fas expression is correlated with malignant transformation and biologic aggressiveness in pancreatic adenocarcinomas. This may represent a mechanism by which pancreatic tumor cells become resistant to apoptosis and escape immune surveillance in vivo.     

Fas和FasL及Caspase-8在宫颈癌组织中的表达及其临床意义

目的 :研究Fas、FasL及Caspase 8在宫颈癌组织中的表达及其临床意义 ,探讨Fas系统在宫颈肿瘤细胞免疫逃避中的作用。方法 :采用免疫组化S P法检测 5 2例宫颈癌、18例宫颈上皮内瘤样病变、10例慢性宫颈炎及 10例正常宫颈上皮Fas、FasL和Caspase 8蛋白表达情况。结果 :Fas及FasL在宫颈癌中的表达与在慢性宫颈炎及正常组织中表达差异有显著意义 ;Fas阳性表达率随着组织学分级的升高而降低 ,FasL则增高 ,P <0 0 1;Fas及FasL与患者的年龄和临床分期无关 ,P >0 0 5。Caspase 8在宫颈癌中的表达明显低于正常宫颈上皮及慢性宫颈炎 ,P <0 0 1;Caspase 8表达与宫颈癌患者的年龄、临床分期及组织学类别无关。结论 :宫颈癌能通过Fas、Caspase 8低表达及FasL高表达逃避机体免疫监视以促使肿瘤发生发展及转移     

Expression of Fas and Fas ligand in esophageal tissue mucosa and carcinomas.

The Fas ligand (FasL) and its receptor Fas play a key role in the initiation of an apoptotic pathway. We describe the expression of Fas receptor and ligand pair antigens in surgical samples collected from a cohot of 89 patients compared with 89 squamous cell carcinomas (SCCs), 45 dysplasias and 42 normal mucosae of the esophagus. TUNEL method was performed in 89 SCCs. Evaluation of FasL on normal mucosae displayed a heterogeneous immunoreaction in a minority of specimens, whereas SCCs exhibited a more extended and homogeneous reactivity. Fas-positive carcinoma cells revealed frequent apoptosis. Furthermore, a significantly longer disease-free survival can be observed in patients with Fas-positive tumors than in Fas-negative carcinomas and in patients with FasL-negative tumors than in FasL-positive carcinomas. In conclusion, FasL expression may play an important role in tumor progression. On the other hand, Fas-expressing carcinoma cells were associated with frequent apoptosis. Both FasL and Fas expressions correlate with prognostic significance in esophageal SCCs.     

Addressing the "Fas counterattack" controversy: blocking fas ligand expression suppresses tumor immune evasion of colon cancer in vivo

Fas ligand (FasL/CD95L) is a transmembrane protein belonging to the tumor necrosis factor superfamily that can trigger apoptotic cell death following ligation to its receptor, Fas (CD95/APO-1). Expression of FasL may help to maintain tumor cells in a state of immune privilege by inducing apoptosis of antitumor immune effector cells-the "Fas counterattack." However, the ability of FasL to mediate tumor immune privilege is controversial due to studies that indicate FasL has both pro- and anti-inflammatory activities. To resolve this controversy and functionally define the role of FasL in tumor immune evasion, we investigated if suppression of endogenously expressed FasL in colon tumor cells resulted in reduced tumor development and improved antitumor immune challenge in vivo. Specifically, FasL expression in CMT93 colon carcinoma cells was down-regulated following stable transfection with a plasmid encoding antisense FasL cDNA. Down-regulation of FasL expression had no effect on tumor growth in vitro but significantly reduced tumor development in syngeneic immunocompetent mice in vivo. Tumor size was also significantly decreased. Reduced FasL expression by tumor cells led to increased lymphocyte infiltration. The overall level of neutrophils present in all of the tumors examined was low, with no difference between the tumors, irrespective of FasL expression. Thus, down-regulation of FasL expression by colon tumor cells results in an improved antitumor immune challenge in vivo, providing functional evidence in favor of the "Fas counterattack" as a mechanism of tumor immune evasion.     

Fas ligand expression in esophageal carcinomas and their lymph node metastases

BACKGROUND: Although esophageal adenocarcinomas (EADCA) have been shown to have substantially reduced or absent Fas expression, the status of Fas ligand (FasL) in these tumors, especially adenocarcinomas, is largely unknown. METHODS: Using immunohistochemistry, the authors investigated FasL expression in sections of formalin fixed, paraffin embedded tissue from 13 EADCA. They also studied sections of 15 esophageal squamous cell carcinomas (ESCCA) and of lymph node metastases from 7 EADCA and 4 ESCCA. The percentage of FasL positive cells in each tumor was recorded. FasL expression in EADCA was compared with that in ESCCA and with lymph node status. Statistical analysis was performed using the Fisher exact test. RESULTS: No specific staining pattern was seen in adenocarcinomas. In ESCCA, FasL was often located in the cells at the periphery of tumor nests. All (100%) of EADCA showed FasL expression in greater than 25% of the cancer cells, and all were associated with lymph node metastasis. Fifty-three percent of ESCCA showed FasL expression in greater than 25% of the cancer cells and 33% had lymph node metastasis. Expression of FasL in greater than 25% of tumor cells was associated with a significantly higher incidence of lymph node metastasis (P=0.0001). All lymph node metastases from esophageal carcinomas showed FasL immunoreactivity in greater than 50% of the metastatic tumor cells. CONCLUSIONS: FasL expression in greater than 25% of cancer cells correlates with a high incidence of lymph node metastasis in esophageal carcinomas. All cancer metastases in lymph nodes express FasL in >50% of the cells. These findings indicate that FasL plays an important role in the immune evasion and metastasis of esophageal carcinomas.     

Fas and Fas ligand interactions in malignant disease

Apoptosis has been implicated in tumor development and progression. Fas (CD95) and Fas ligand (FasL) are an interacting receptor ligand pair that elicits apoptosis in many cell types. Although originally described as proteins regulating peripheral immune tolerance, accumulating evidence suggests that Fas/FasL may play an important role in carcinogenesis, tumor outgrowth, and metastasis. This review summarizes our current knowledge about the regulation of Fas and FasL expression, Fas signaling, soluble Fas production, the role(s) of Fas and FasL in hematopoietic and non-hematopoietic tumorigenesis and progression, and the potential application of Fas-induced apoptosis in cancer therapy.     

Fas/Fas ligand system and apoptosis induction in testicular carcinoma

BACKGROUND: Tumor-infiltrating, Fas ligand (FasL)-expressing lymphocytes are able to eliminate Fas-bearing tumor cells by apoptosis induction. Activated cytotoxic T-cells that express Fas may enter apoptosis in the presence of FasL tumor cells. To date, no studies of patients with testicular carcinoma have correlated the differential expression of Fas and FasL in both cell types with the corresponding apoptotic index (AI). METHODS: Fas and FasL were investigated immunohistochemically in paraffin embedded tissue sections from 25 patients with nonseminomatous testicular tumors. The percentages of positive cells and the ratios of Fas cells to FasL cells were correlated with the AI of tumor cells and lymphocytes, respectively, using Spearman correlations. RESULTS: No association was found between the rate of FasL positive cells and AI of the other cell type or between the rate of Fas positive cells and the AI of the same cell type. Ratios between Fas positive cells and FasL positive cells were not correlated with the AI; however, a significant positive correlation was found between the AI of tumor cells and the AI of lymphocytes. CONCLUSIONS: It seems unlikely that the Fas/FasL system is responsible for immune escape of the tumor in testicular carcinoma. Rather, the significant positive correlation between the AIs of tumor cells and lymphocytes implicate a previously unknown mechanism of apoptosis induction in both cell types.     

宫颈癌组织中Fas、FasL及caspase-8表达及其临床意义

目的 研究Fas、FasL及caspase-8蛋白在宫颈癌组织中的表达及其临床意义，并探讨其在宫颈肿瘤细胞免疫逃避中的作用。方法 采用免疫组化法检测52例宫颈癌、18例宫颈上皮内瘤祥病变组织(CIN)及其肿瘤浸润淋巴细胞(TIL)，10例慢性宫颈炎，10例正常宫颈上皮中Fas、FasL和caspase-8蛋白表达情况。结果 Fas及FasL在宫颈癌组织中的表达率与慢性宫颈炎及正常组织比较有显著性差异(P＜0．05，P＜0．01)，宫颈鳞癌明显高于宫颈腺癌(P＜0．05，P＜0．01)。Fas阳性表达率随着组织学分级的升高而降低，FasL则增高(P＜0．01)；有淋巴结转移者FasL阳性表达率高于无淋巴结转移者(P＜0．01)；Fas及FasL表达与患者年龄、临床分期无关(P＞0．05)。宫颈癌TIL的Fas及FasL表达明显高于CIN(P＜0．01)；caspase-8在宫颈癌组织中的表达明显低于正常宫颈上皮及慢性宫颈炎组织(P＜0．01)，caspase-8表达与宫颈癌患者年龄，临床分期，组织学类型无关(P＞0．05)，有淋巴结转移者明显低于无淋巴结转移者(P＜0．05)，随着组织学分级的降低，caspase-8表达亦明显降低，但无显著性差异。结论 宫颈癌能通过Fas，caspase-8低表达及FasL高表达，逃避机体免疫监视以促使肿瘤发生发展及转移。     

Fas and Fas ligand expression in tumor cells and in vascular smooth-muscle cells of colonic and renal carcinomas.

CD95/APO-1 ligand (FasL) is implicated in the maintenance of immune privileged sites by inducing apoptosis of activated infiltrating T lymphocytes. Therefore, progressive tumors might express high levels of FasL and develop as immune privileged sites. In this study, we investigated the expression of FasL and CD95/APO-1 (Fas, the FasL-receptor) in vitro in rat adenocarcinoma cell lines and the localization in situ in normal human kidney and colon and in their adenocarcinomas. The rat cell line PROb (a progressive tumor in vivo) expressed a higher level of FasL than the sister cell line REGb (a regressive tumor in vivo), as detected by flow cytometry. The 2 cell lines expressed the same level of Fas, but were resistant to FasL-induced apoptosis. In human tissue, both kidney and colon extracts expressed FasL by Western blot. Further investigations, using immunohistochemical staining of paraffin sections, showed that normal colon mucosa expressed Fas and FasL in crypt epithelial cells in the subnuclear compartment. Normal kidney showed Fas and FasL labeling mostly restricted to epithelial cells of proximal tubules and Henlé's loop, showing that this expression is not uniform throughout the organ. Smooth-muscle cells of muscularis propria and blood vessels in and around the tumors were also intensely but more uniformly labeled. In colon-cancer cells, FasL expression remained strong, whereas Fas expression was significantly reduced. A similar reduction in Fas expression was noted in renal-cancer cells. Tumor-infiltrating immune cells of the macrophage lineage do not express FasL. Our results show that smooth-muscle cells of muscularis propria and blood vessels are able to express FasL and to a slight extent Fas. In normal epithelial cells of colon and kidney, Fas and FasL are often co-expressed. The reduced expression of Fas in corresponding cancer cells in combination with the ability to express FasL might facilitate immune escape.     

Fas ligand expressed in colon cancer is not associated with increased apoptosis of tumor cells in vivo

Expression of Fas ligand (FasL/CD95L) may help to maintain colon cancers in a state of immune privilege by inducing apoptosis of antitumor immune effector cells. Colon tumor-derived cell lines appear to be relatively insensitive to apoptosis mediated by their own or exogenous FasL in vitro, despite expression of cell surface Fas. In our present study, we sought to investigate if FasL upregulated in human colon cancers leads to any increase in apoptosis of the tumor cells in vivo. FasL and Fas receptor (APO-1/CD95) expression by tumor cells were detected immunohistochemically. Apoptotic tumor cell death was detected by immunohistochemistry for caspase-cleaved cytokeratin-18. FasL expression did not correlate with the extent of apoptosis of tumor cells. There was no significant local difference in the frequency of apoptosis of tumor cells between tumor nests that expressed FasL (mean = 2.4%) relative to those that did not (mean = 2.6%) (p = 0.625, n = 10; Wilcoxon signed rank). FasL expressed by the tumor cells appeared to be functional, since FasL expression in tumor nests correlated with diminished infiltration of tumor-infiltrating lymphocytes (TILs). TILs were detected using immunohistochemistry for CD45. Expression of FasL by tumor nests was associated with a mean 4-fold fewer TILs relative to FasL-negative nests (range 2.4-33-fold, n = 10, p < 0.003). Together, our results indicate that colon tumors are insensitive to FasL-mediated apoptosis in vivo.     

Expression of Fas ligand (CD95L) in primary malignant melanoma and melanoma metastases is associated with overall survival

BACKGROUND: There is increasing evidence that the Fas/Fas ligand (FasL) system is involved in tumor-mediated immune suppression. The purpose of this study was to investigate the effect of Fas (CD95) as well as FasL (CD95L) expression in primary malignant melanoma and melanoma metastases on overall survival (OS). PATIENTS AND METHODS: 19 patients with metastatic malignant melanoma who were treated with different dacarbazine (DTIC)-based chemotherapy regimens were included in this study. From each patient, primary melanoma biopsies and biopsies from metastases were histologically evaluated. Immunohistology was performed with antibodies to Fas/CD95 and FasL/CD95L. Differences in OS were plotted using the Kaplan-Meier method and compared by the log rank test. RESULTS: Fas/CD95 and FasL/CD95L expression was detected in 73.7 and 63.2% of primary melanomas, respectively. In metastases, expression of both Fas/CD95 (63.2%) and FasL/CD95L (47.4%) was markedly decreased. Presence of FasL/ CD95L expression in primary melanoma resulted in significantly (p = 0.024) prolonged OS compared with FasL/CD95L-negative high-risk primary melanomas. In contrast, loss of FasL/CD95L expression in melanoma metastases resected before chemotherapy was associated with significantly prolonged median survival (p = 0.0139). CONCLUSION: Presence of FasL/CD95L expression in primary malignant melanoma and the loss of FasL/ CD95L expression in metastases seem to be positive prognostic factors.