Prognostic significance of Fas and Fas ligand system-associated apoptosis in gastric cancer

FAS gene expression, prognostic significance and molecular interactions in lung cancer

Introduction

FAS has been implicated in the development of various cancers, but its involvement in lung cancer has not been systematically characterized. In this study, we performed data mining in online tumor databases to investigate the expression, methylation, alterations, protein interactions, co-expression and prognostic significance of FAS in lung cancer.

Method

The expression, prognostic significance and molecular interactions of FAS in lung cancer was mined and analyzed using GENT2, GEPIA2, UALCAN, cBioPortal, STRING, GeneMANIA, UCSC Xena, Enrichr, and OSluca databases. FAS expression was subsequently investigated at the protein level in samples from 578 lung cancer patients to understand its protein-level expression. In vitro validation of FAS gene expression was performed on H1299, H1993, A549 and HBE cell lines.

Result

We found that the expression of FAS was significantly downregulated in both lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) compared to normal lung tissue. In addition, we observed a higher level of FAS promoter methylation in LUSC tissue than in normal tissue. FAS alterations were rare (1.9%) in lung cancer samples, with deep deletions being more common than missense mutations, which occurred mainly in the TNFR-like cysteine-rich domain and the death domain. We also identified a list of proteins interacting with FAS and genes co-expressed with FAS, with LUAD having 11 co-expressed genes and LUSC having 90 co-expressed genes. Our results also showed that FAS expression has limited prognostic significance (HR=1.302, 95% CI=0.935-1.139, P=0.530). Protein level investigation revealed that FAS expression varied among individuals, with nTPM values ranging from 5.2 to 67.2.

Conclusion

This study provides valuable insights into the involvements and characteristics of FAS in lung cancer. Further studies are needed to investigate the clinical significance of FAS alterations in lung cancer and to explore the potential of targeting FAS for therapeutic intervention.

Intrinsic and extrinsic pathways of apoptosis: Role in cancer development and prognosis

Apoptosis, also named programmed cell death, is a fundament process required for morphogenetic homeostasis during early development and in pathophysiological conditions. It is come into existence in 1972 by work of Kerr, Wyllie and Currie and later on investigated during the research on development of the C. elegans. Trigger by several stimuli, apoptosis is necessary during the embryonic development and aging as homeostatic mechanism to control the cell population and also play a key role as defense mechanism against the immune responses and elimination of damaged cells. Cancer, a genetic disease, is a growing burden on the health and economy of both developing and developed countries. Every year there is tremendously increasing in the number of new cancer cases and mortality rate. Although, there is a significant improvement have been made in biotechnological and bioinformatic fields however, the therapeutic advantages and cancer etiology is still under explored. Several studies determined the deregulation of different apoptotic components during the cancer development and progression. Apoptosis relies on activation of distinct signaling pathways that are often deregulated in cancer. Thus, exploring the single or more than one apoptotic component underlying their expression in carcinogenesis could help to track the disease progression. Current book chapter will provide the several evidences supporting the use of different apoptotic components as prognosis and prediction markers in various human cancer types.

High cytotoxic T-lymphocyte-associated antigen 4 and phospho-Akt expression in tumor samples predicts poor clinical outcomes in ipilimumab-treated melanoma patients

Ipilimumab, a fully human monoclonal antibody against cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), is the first immune checkpoint inhibitor approved for the treatment of unresectable melanoma on the basis of its overall survival (OS) benefit. However, ipilimumab is associated with significant immune-related adverse events. We hypothesized that biomarker exploration of pretreatment tumor samples and correlation with clinical outcome would enable patient selection with an increased benefit/risk ratio for ipilimumab therapy. At the University of Texas MD Anderson Cancer Center, a total of 81 advanced melanoma patients were treated on the Ipilimumab Expanded Access Program from 2007 to 2008. Using immunohistochemistry, we analyzed the expression of immune checkpoint (CTLA-4, PD-1, PD-L1) and Akt-pathway proteins in formalin-fixed tumor tissue. Associations between these biomarkers and progression-free survival (PFS) and OS were analyzed with univariate and multivariate Cox proportional-hazards models. There was a significant correlation between high CTLA-4 protein expression levels in tumor cells and risk of death (P=0.02) and decreased PFS (P=0.023). In addition, high expression of CTLA-4 in peritumoral lymphocytes correlated with poor OS (P=0.023). In multivariate analysis, patients with high CTLA-4 and phospho-Akt (p-Akt) expression correlated with poor OS (log-rank test, P=0.039) and PFS (log-rank test, P=0.014). High levels of CTLA-4 and p-Akt expression in pretreatment tumor cells in melanoma patients were associated with poor clinical outcomes. Immunohistochemistry analysis of CTLA-4 and p-Akt in pretreatment tumor samples provides useful biomarkers that may enable improved patient selection for ipilimumab therapy. Prospective clinical studies are warranted to investigate the predictive value of these biomarkers.

Prognostic Investigations of Expression Level of Two Genes FasL and Ki-67 as Independent Prognostic Markers of Human Retinoblastoma

In this study, expression of FasL and Ki-67 messenger RNA (FasL and Ki-67 mRNA) in human retinoblastoma (HRB) was examined by the immunohistochemistry method and quantitative real-time PCR. Positive expression of Ki-67 in tumor cells was detected in 16 of 30 patients (53.33%), and only 9 (30%) of the tissues from patients with retinoblastoma showed positive staining for FasL. Our results revealed that FasL expression was significantly higher in tumor tissue with invasion compared with the noninvasion form (p = 0.033). Ki-67 expression was markedly increased in tumor tissues with invasion compared with the noninvasion group (p = 0.04), but no significant correlation was found between FasL expression and differentiation (p > 0.05). In addition, Ki-67 expression was strongly linked to differentiation (p < 0.002). Expression of these FasL was correlated with shorter overall survival of patients, but its expression was not significantly associated with overall survival (p = 0.15). The impact of Ki-67 expression on survival in patients was also evaluated. Ki-67 expression level was not found to be significantly associated with shorter survival (Kaplan–Meier; p = 0.09). Univariate analysis revealed that massive choroidal invasion was correlated with poor prognosis. Taken together, the data suggest that massive choroidal invasion is also an important indicator of poor prognosis for HRB.

Elevated Serum CD95/FAS and HIF-1α Levels, but Not Tie-2 Levels, May Be Biomarkers in Patients With Severe Endometriosis: A Preliminary Report

STUDY OBJECTIVE

To evaluate serum values of cluster of differentiation 95 (CD95/FAS), hypoxia-inducible factor 1-alpha (HIF-1α), and tyrosine kinase receptor 2 (Tie-2) as possible biomarkers of disease presence and severity in women with endometriosis, and to characterize the changes in these values in women with stage I/II and stage III/IV endometriosis.

DESIGN

Prospective study (Canadian Task Force classification I).

SETTING

University hospital.

PATIENTS

Thirty women with endometriosis and 30 healthy women without endometriosis.

INTERVENTION

For the diagnosis of endometriosis and prediction of its severity, we measured the serum levels of CD95/FAS, which assess apoptotic conditions, and of HIF-1α and Tie-2, which assess angiogenesis. Endometriosis was diagnosed and staged through surgical laparoscopy and later confirmed histologically. During the surgery, the patients with endometriosis were divided into 2 groups based on disease stage. Eleven patients had stage I/II endometriosis, and 19 had stage III/IV endometriosis.

MEASUREMENTS AND MAIN RESULTS

Endometriosis was associated with increased serum CD95/FAS and HIF-1α levels, but not Tie-2 levels. We also determined that stage III/IV endometriosis was associated with higher serum CD95/FAS and HIF-1α levels, but not Tie-2 levels, compared with stage I/II endometriosis.

CONCLUSION

Endometriosis, in accordance with its severity, increases serum CD95/FAS and HIF-1α levels, but not Tie-2 levels. These biomarkers may be useful for reproductive surgeons to improve the quality of counseling women about the presence and severity of endometriosis.

A new pN staging system based on both the number and anatomic location of metastatic lymph nodes in gastric cancer

BACKGROUND

Our aim was to establish a new pN staging system for gastric cancer based on the number and location of metastatic lymph nodes (MLNs) and to compare it with other systems.

METHODS

We retrospectively analyzed the prognostic data of 521 gastric cancer patients who underwent curative resection. Survival analyses were used to establish a pN staging system that considers both the number and location of MLNs and to compare discriminatory ability and monotonicity of gradients (linear trend χ (2) score), homogeneity ability (likelihood ratio test), and prognostic stratification ability (Akaike information criterion) between Japanese Gastric Cancer Association (JGCA) and Union for International Cancer Control (UICC) systems.

RESULTS

Cut-point survival analysis divided pN(+) patients into two groups: Nxn1~6 and Nxn≥7. N0, N1, N2, and N3 (the previous classifications) were replaced by N0, N1n1~6, N2n1~6, and N1n≥7 + N2n≥7 + N3n1~6 + N3n≥7, respectively. Compared with two widely used staging systems, the new system had the highest likelihood ratio test [106.06 (new) vs 95.09 (JGCA) vs 94.33 (UICC)] and linear trend χ (2) scores [102.30 (new) vs 89.12 (JGCA) vs 86.97(UICC)] and the lowest Akaike information criterion (AIC) score [2,283.88 (new) vs 2,285.31 (JGCA) vs 2,299.88 (UICC)].

CONCLUSION

A new pN staging system based on the number and location of MLNs is an efficient prognostic indicator of the survival of patients with gastric cancer following radical surgery.

Analysis of methylation and mRNA expression status of FADD and FAS genes in patients with oral squamous cell carcinoma

Background: Apoptosis is an important mechanism that is responsible for the physiological deletion of harmful, damaged, or unwanted cells. Changed expression of apoptosis-related genes may lead to abnormal cell proliferation and finally to tumorigenesis. Our aims were to analyze the promoter methylation and gene expression profiles of FADD and FAS genes in risk of OSCC. Material and Methods: we analyze the promoter methylation status of FADD and FAS genes using Methylation - Specific PCR (MSP) in 86 OSCC tissues were kept in paraffin and 68 normal oral tissues applied as control. Also, FADD and FAS genes expression were analyzed in 19 cases and 20 normal specimens by Real-Time Reverse-Transcripts PCR. Results: Aberrant promoter methylation of FADD and FAS genes were detected in 12.79 % (11 of 86) and 60.46 % (52 of 86) of the OSCC cases, respectively, with a significant difference between cases and healthy controls for both FADD and FAS genes (P<0.001). The gene expression analysis showed statistically significant difference between cases and healthy controls for both FADD (p<0.02) and FAS (p<0.007) genes. Conclusions: To the best our knowledge, the data of this study are the first report regarding, the effect of promoter hypermethylation of the FADD and FAS genes in development of OSCC. To confirm the data, it is recommended doing further study in large sample sizes in various genetic populations.

Key words:OSCC, FADD, FAS, DNA methylation, gene expression.

Functional polymorphisms in apoptosis pathway genes and survival in patients with gastric cancer

The FAS, FAS ligand (FASL), and CASP8 are key regulators for apoptosis and their deregulations play an important role in carcinogenesis. However, the effects of promoter polymorphisms of the FAS, and FASL, and CASP8 genes on the survival of gastric cancer are unknown. In this study, we investigated the association of four polymorphisms (FAS -1377G>A, -670A>G, FASL -844C>T, and CASP8 -652 6N ins>del) with the clinical outcome of 940 gastric cancer patients in a Chinese population. The correlation between genotype and survival outcomes was assessed by the Kaplan-Meier method, Cox proportional hazards models and the log-rank test. Our results revealed that individuals with CASP8 -652 6N ins/del+del/del genotypes had a decreased risk of death compared with those with ins/ins genotype (log-rank P=0.005; hazard ratio=0.75, 95% confidence interval=0.62-0.92). The protective effect of the del allele was further confirmed in subgroups of patients with tumor size ≤ 5 cm (0.66, 0.50-0.86) and T2 depth invasion (0.59, 0.37-0.94), but no significant association was observed in the subgroups of lymph node metastasis (0.67, 0.47-0.97), and distance metastasis (0.73, 0.60-0.90). Our findings suggest that, if validated in different independent populations, the CASP8 -652 6N ins>del polymorphism may serve as a promising genetic marker for gastric cancer prognosis.

High Fas expression in gastric carcinoma cells as a factor correlating with the occurrence of metastases to regional lymph nodes

PURPOSE

The aim of this study was to evaluate the correlation of the expression of Fas and Fas-L proteins in gastric carcinoma cells on the occurrence of metastases to regional lymph nodes.

MATERIAL/METHODS

The study included 89 patients treated surgically for gastric carcinoma. The evaluated clinicomorphological parameters were verified based on both histopathological material collected at surgery and intraoperative image. Fas and Fas-L expression was evaluated immunohistochemically in the neoplastic tissue of the removed gastric tumors.

RESULTS

A statistically significant positive correlation between Fas expression in gastric carcinoma cells and the number of regional lymph nodes affected by metastases was observed (p<0.05). No such correlation was noticed with respect to Fas-L. A statistically significant correlation between the depth of neoplastic infiltration of the stomach wall (T feature) and the number of affected lymph nodes was observed (p<0.05). No statistically significant correlations in the other examined clinicomorphological features and the number of metastatic lymph nodes was observed.

CONCLUSION

A positive Fas expression correlates with more frequent occurrence of metastases to regional lymph nodes. Determination of this protein expression in cancer cells prior to surgery may be helpful for planning the surgical procedure, especially with respect to the extent of lymph node excision.

FAS/FASL expression profile as a prognostic marker in squamous cell carcinoma of the oral cavity

FAS/FASL altered expression may cause tumor protecting immunomodulation, with a direct impact on patient prognosis. FAS expression was studied in 60 squamous cell carcinomas of the oral cavity. FAS expression did not show a significant association with tumor histopathological characteristics, but was significantly associated with lymph node positivity. FAS expression was significantly associated with disease specific death and negative FAS expression was an independent risk factor, increasing risk 4 times when compared to positive expression. When FAS and FASL expression results were combined, we were able to define high, intermediate and low risk profiles. Disease-free and disease-specific survival were significantly correlated with FAS/FASL expression profiles. The high risk category was an independent marker for earlier disease relapse and disease-specific death, with approximately 4- and 6-fold increased risk, respectively, when compared to the low risk profile. Risk profiles based on FAS/FASL expression showed that high risk was significantly associated with increased disease relapse and death, as well as shorter disease-free or disease-specific survival. This categorization, added to patient clinical data, may facilitate the choice of therapy, minimizing treatment failure and increasing disease control.

Soluble Fas might serve as a diagnostic tool for gastric adenocarcinoma

BACKGROUND

Fas (Apo-1/CD95) and its specific ligand (FasL) are key elements in apoptosis. They have been studied in different malignancies but there are few published studies about the soluble forms of these markers (i.e. sFas/sFasL) in gastric cancer. We have compared the serum levels of sFas/sFasL in gastric adenocarcinoma patients and cases with pre-neoplastic lesions as potential markers for early diagnosis, and investigated their relation with clinicopathological characteristics.

METHODS

Fifty-nine newly-diagnosed cases of gastric adenocarcinoma who had undergone gastrectomy, along with 62 endoscopically- and histologically-confirmed non-cancer individuals were enrolled in this study. sFas/sFasL serum levels were detected by Enzyme Linked Immunosurbent Assay.

RESULTS

Mean serum sFas level was significantly higher in gastric cancer patients than in control group (305.97 +/- 63.71 (pg/ml) vs. 92.98 +/- 4.95 (pg/ml), P < 0.001); while the mean serum level of sFasL was lower in patients with gastric adenocarcinoma (0.138 +/- 0.04 (pg/ml) vs. 0.150 +/- 0.02 (pg/ml), P < 0.001). Mean serum levels of sFas/sFasL were significantly different in both intestinal/diffuse and cardiac/non-cardiac subtypes when compared to the control group (P < 0.001). There was an increase in the serum level of sFas from the first steps of pre-neoplastic lesions to gastric adenocarcinoma (P < 0.001). Patients who had no lymph node involvement (N0) showed significantly higher serum levels of sFas compared to others (P = 0.044).

CONCLUSIONS

Production of sFas may play a critical role in the carcinogenesis of intestinal-type gastric cancer. sFas serum level may serve as a non-invasive tool for early diagnosis of gastric cancer.

Apoptosis and Microvessel Density in Gastric Cancer: Correlation with Tumor Stage and Prognosis

Gastric cancer remains one of the most common human malignancies with a poor prognosis. Apoptosis is known to be a programmed cell death and its inhibition is involved in the unregulated cellular growth that leads to neoplasms. Microvessel density (MVD) has been investigated as a promoting factor for angiogenesis with conflicting results about its relation to survival. The aim of our study was to search a correlation between these factors and some clinicopathological features and prognosis. Identification of apoptotic cells was performed applying the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling technique and recorded as apoptotic index (A.I.), whereas monoclonal antibodies were used for the study of MVD. A significant correlation was found between low and high A.I. and the subgroup of patients in Stages I and II (P < 0.02); 20 per cent of patients with a low A.I. showed an overall survival longer than 5 years versus 44 per cent of patients with an high A.I. (P = 0.041). High MVD was significantly related to the T stage ( P = 0.036) and to a poorer 5-year overall survival (P < 0.05). Further studies are required to confirm the role of apoptosis and MVD in the development and progression of gastric cancer.

Interventional effect of Ginkgo biloba extract on the progression of gastric precancerous lesions in rats

OBJECTIVE

To investigate the effect of Ginkgo biloba extract on gastric precancerous lesions in rats.

METHODS

80 4-week-old Wistar rats were randomly divided into four groups: a control group, a model group, a low and a high dose Ginkgo biloba extract intervention group; 20 in each group. Gastric precancerous lesions were induced by giving them 100 mg/L N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) solution to drink ad libitum for 20 weeks. In addition to the MNNG, the intervention groups were lavaged with Ginkgo biloba extract (0.5 mg/kg/d in the low dose group, 1.5 mg/kg/d in the high dose group) for 20 weeks. Starting from week 21 all the rats were fed with normal rat chow and tap water. At the end of week 30 the rats were killed. The histopathological changes of their gastric mucosa, ISA, NGI, the serum and gastric mucosal SOD/MDA and the expressions of oncogenes were studied.

RESULTS

The incidence of mild to severe intestinal metaplasia and dysplasia were significantly lower in the intervention groups than those in the model group (P < 0.01). The ISA and NGI in the intervention groups were significantly lower than those in the model group (P < 0.01). In the intervention groups the activity of SOD was increased and the concentration of MDA was decreased (P < 0.01). Expressions of Bcl-2, c-myc and FasL decreased in the intervention groups, whereas the expression of Fas increased. When compared with the model group, the differences were statistically significant (P < 0.01, P < 0.05, respectively).

CONCLUSION

Ginkgo biloba extract can increase anti-oxidative activity and inhibit the progression of gastric precancerous lesions via the regulation of cell proliferation and apoptosis.

FAS and FAS ligand polymorphisms in the promoter regions and risk of gastric cancer in Southern China

The FAS and FAS ligand (FASLG) system plays a key role in regulating apoptotic cell death, and corruption of this signaling pathway has been shown to participate in tumorigenesis. Functional promoter polymorphisms of the FAS and FASLG genes can alter transcriptional activities and thus alter risk of cancer. We hypothesized that the FAS -1377G>A, FAS -670A>G, and FASLG -844T>C polymorphisms in the promoter regions are associated with risk of gastric cancer. In a population-based case-control study of 332 gastric cancer cases and 324 controls, we genotyped these three polymorphisms and evaluated their association with risk of gastric cancer. We found that the FAS and FASL genotypes and the FAS haplotypes had no significant associations with risk of gastric cancer. In addition, there was no significant interaction between the FAS and FASL polymorphisms in the development of gastric cancer. The FAS and FASLG polymorphisms may not contribute to risk of gastric cancer in the southern Chinese population.

The herb medicine formula "Yang Wei Kang Liu" improves the survival of late stage gastric cancer patients and induces the apoptosis of human gastric cancer cell line through Fas/Fas ligand and Bax/Bcl-2 pathways

The herb medicine formula "Yang Wei Kang Liu" (YWKLF) has been used to inhibit the metastasis of human gastric cancer to prolong patient survival. In this study, we evaluated the effect of combination of chemotherapy with YWKLF on the survival of stage IV gastric cancer patients and the potential mechanisms of YWKLF by focusing on its capacity to activate apoptotic pathways in human gastric cancer cell line MGC-803. We found that combination of chemotherapy with oral administration of YWKLF significantly increased the survival of stage IV gastric cancer patients. In an approach of "serum pharmacology" in which sera were collected from rabbits orally administered with YWKLF and examined for their anti-tumor cell activity in vitro, we observed that sera from rabbits administered with YWKLF induced the apoptosis of MGC-803 cells by causing the loss of mitochondrial membrane potential, increasing the expression of Fas protein and Bax mRNA, as well as down-regulating Fas-L mRNA. Our results suggest that activation of major pro-apoptotic pathways may account for the anti-gastric cancer activity of YWKLF, which may provide a basis for isolation and identification of more highly effective anti-cancer components.

The "Fas counterattack" is not an active mode of tumor immune evasion in colorectal cancer with high-level microsatellite instability

Microsatellite instability (MSI) is an alternative pathway of colorectal carcinogenesis. It is found in 10% to 15% of sporadic colorectal neoplasms and is characterized by failure of the DNA mismatch-repair system. High-level MSI (MSI-H) is associated with tumor-infiltrating lymphocytes (TILs) and a favorable prognosis. Expression of Fas ligand (FasL/CD95L) by cancer cells may mediate tumor immune privilege by inducing apoptosis of antitumor immune cells. The aim of this study was to investigate the relationship between FasL expression and MSI status in primary colon tumors. Using immunohistochemistry, we detected FasL expression in 91 colorectal carcinoma specimens, previously classified according to the level of MSI as MSI-H (n = 26), MSI-low (MSI-L) (n = 29), and microsatellite stable (n = 36). Tumor-infiltrating lymphocyte density was quantified by immunohistochemical staining for CD3. MSI-H tumors were significantly associated with reduced frequency (P = .04) and intensity (P = .066) of FasL expression relative to non-MSI-H (ie, microsatellite stable and MSI-L) tumors. Higher FasL staining intensity correlated with reduced TIL density (P = .059). Together, these findings suggest that the abundance of TILs found in MSI-H tumors may be due to the failure of these tumor cells to up-regulate FasL and may explain, in part, the improved prognosis associated with these tumors.

Macrophage migration inhibitory factor stimulates angiogenic factor expression and correlates with differentiation and lymph node status in patients with esophageal squamous cell carcinoma

OBJECTIVE

The objectives of this study were: 1) to examine the expression of macrophage migration inhibitory factor (MIF) in esophageal squamous cell carcinoma (ESCC); 2) to see if a relationship exists between MIF expression, clinicopathologic features, and long-term prognosis; and 3) to ascertain the possible biologic function of MIF in angiogenesis.

SUMMARY BACKGROUND DATA

MIF has been linked to fundamental processes such as those controlling cell proliferation, cell survival, angiogenesis, and tumor progression. Its role in ESCC, and the correlation of MIF expression and tumor pathologic features in patients, has not been elucidated.

METHODS

The expression of MIF in tumor and nontumor tissues was examined by immunohistochemical staining. Concentrations of MIF, vascular endothelial growth factor (VEGF), and interleukin-8 (IL-8) in patients' sera and in the supernatant of tumor cells culture were examined by ELISA. Correlations with clinicopathologic factors were made.

RESULTS

In 72 patients with ESCC, intracellular MIF was overexpressed in esophagectomy specimens. The expression of MIF correlated with both tumor differentiation and lymph node status. The median survival in the low-MIF expression group (<50% positively stained cancer cells on immunohistochemistry) and high expression group (>/=50% positively stained cancer cells) was 28.3 months and 15.8 months, respectively (P = 0.03). The 3-year survival rates for the 2 groups were 37.7% and 12.1%, respectively. MIF expression was related to microvessel density; increased MIF serum levels also correlated with higher serum levels of VEGF. In addition, in vitro MIF stimulation of esophageal cancer cell lines induced a dose-dependent increase in VEGF and IL-8 secretion.

CONCLUSIONS

These results demonstrate, for the first time, that human esophageal carcinomas express and secrete large amounts of MIF. Through its effects on VEGF and IL-8, MIF may serve as an autocrine factor in angiogenesis and thus play an important role in the pathogenesis of ESCC.

Prognostic significance of metastatic lymph node size in patients with gastric cancer

BACKGROUND

Patients with gastric cancer that has metastasized to the lymph nodes are a heterogeneous population with a variable prognosis. Stratification of these patients into prognostic groups is necessary for optimal adjuvant therapy.

METHODS

The study comprised 715 patients who had undergone curative resection of a gastric neoplasm. Lymph nodes were sectioned, stained with haematoxylin and eosin, and the diameter of the largest metastatic lymph node (MLN) was measured. Patients with metastatic nodes were divided into groups n1 and n2 according to the size of the MLN. The cut-off level was set at 7 mm by a two-sample log rank test; patients in group n1 had a MLN size of 7 mm or less and those in group n2 had a MLN of 8 mm or more.

RESULTS

Patients were stratified into significant prognostic groups by both the Union International Contra la Cancrum (UICC) node (N) stage and MLN size (n group). The UICC N-stage subcategories were further divided into prognostic groups according to MLN size (n group). On multivariate analysis the MLN size remained independently significant in terms of overall and disease-free survival rates, and the UICC N stage was not significant, independently of the n group. Node-positive patients with fewer than 15 lymph nodes removed at operation could also be stratified into prognostic groups by the n group. Stratification according to the TNM stage and by MLN size was superior to existing UICC TNM staging.

CONCLUSION

This new method may help clinicians to design a more appropriate treatment strategy for patients with gastric cancer.

Association between RCAS1 expression and clinical outcome in uterine endometrial cancer

RCAS1, which acts as a ligand for a putative receptor on immune cells such as peripheral lymphocytes and natural killer cells, is strongly expressed in human cancers. RCAS1 can induce these cells to undergo apoptotic cell death, which suggests that RCAS1 expression may prohibit the stromal reaction occurring in a tumour. To clarify the clinical significance of RCAS1 expression in uterine endometrial cancer, we analysed the association between RCAS1 expression and clinicopathologic variables by statistical methods. With the use of immunohistochemical techniques, we performed a retrospective study of RCAS1 expression in resected tumour tissue from 147 patients with uterine endometrial cancer. We evaluated the statistical correlation between RCAS1 expression and clinicopathologic variables. RCAS1 was expressed in 106 of 147 patients with uterine endometrial cancer; 30 of these 147 patients showed RCAS1 overexpression. Overexpression of RCAS1 was significantly correlated with age at surgery, stage, extent of myometrial invasion, and positive peritoneal cytologic results. Multivariate analysis revealed that RCAS1 expression and metastasis were clinically significant prognostic factors for the overall survival. These findings indicated that analysis for RCAS1 expression can provide crucial information about the clinical behaviour of uterine endometrial cancer, which may be valuable for the management of patients with this disease.

Prognostic relevance of Fas (APO-1/CD95) ligand in human colorectal cancer

OBJECTIVE

Fas ligand (FasL) is an important mediator of immune function and induces apoptosis by binding to its receptor Fas on sensitized cells. It has recently been shown that malignancies may express FasL and acquire immune privilege by inducing apoptosis of lymphocytes. Acquired resistance to Fas mediated apoptosis is known to be an early event in carcinogenesis. The aim of this study was to determine the extent of FasL expression in patients with colorectal cancer and examine its relationship with several prognostic pathological features and survival.

DESIGN AND METHODS

Sixty-eight patients (median age 66 years) with colorectal cancer, whose diagnosis was made between 1988 and 1991 and in whom long-term follow-up was available, were evaluated. The tumours were of varying stages at diagnosis (eight Dukes' A, 28 Dukes' B, 23 Dukes' C and nine Dukes' D). The expression of FasL was detected immunohistochemically with a rabbit polyclonal IgG using the DAKO EnVision+ System. The specificity of FasL binding was confirmed by pre-incubation of the antibody with the immunizing peptide prior to staining. The relationship with several pathological features was determined using Kendall's tau-b correlation. Overall survival was estimated using the Kaplan-Meier product limit curves. Differences in observed survival were tested for statistical significance using the Mantel-Haenszel log rank test. Both the extent and intensity of staining were graded by a blinded observer.

RESULTS

FasL was predominantly expressed in tumour epithelial cells in 88% of the cases. The positive staining of tumours varied in extent. FasL staining was higher in earlier Dukes' stage tumours in that the extent of FasL staining negatively correlated with Dukes' stage (Kendall tau-b = -0.22, P = 0.038). Consistent with this, the overall survival was better with a greater extent of FasL expression (log rank chi2 = 5.68, P = 0.017). There was a lower extent of FasL expression in mucinous adenocarcinomas (Kendall tau-b = 0.288, P = 0.01) and in those tumours with neural invasion (Kendall tau-b = -0.26, P = 0.03). No relationship was detected between FasL and tumour site, size, margin, differentiation, vascular invasion, necrosis or Crohn's-like reaction.

CONCLUSIONS

FasL is widely expressed in colorectal cancers. This finding suggests that the extent of FasL expression in colorectal tumours is directly related to patients' survival.

Prognostic implications of CD95 receptor expression in clear cell renal carcinomas

The CD95 (Apo-1/Fas) receptor-ligand system is a key regulator of apoptosis. Down-regulation of CD95 receptor and up-regulation of CD95 ligand has been reported in a variety of human tumors and is thought to confer a selective survival advantage. To explore the relevance of the CD95 system for tumor progression and prognosis in clear cell renal cell carcinomas (RCCs), we analyzed CD95 receptor and ligand expression in formalin-fixed tissue from 149 clear cell RCCs by immunohistochemistry. CD95 ligand expression could not be detected in nonneoplastic tubule epithelia and in clear cell RCCs. In contrast, CD95 receptor expression was found in the great majority of clear cell RCCs, and no down-regulation of CD95 receptor protein was evident when compared with nonneoplastic tubule epithelia. Although a significant increase (P = 0.004) of CD95 receptor expression was evident from well-differentiated (G1) to poorly differentiated (G3) RCCs, CD95 receptor expression was not correlated with tumor stage or survival of RCC patients. In conclusion, clear cell RCCs differ from other types of human cancer by their failure to down-regulate CD95 receptor expression or up-regulate CD95 ligand expression during tumor progression. These ex vivo observations suggest that down-regulation of CD95 receptor expression may not provide an additional selective growth advantage to RCC cells and thus further confirm our previous in vitro observations on a functional impairment of CD95-mediated apoptosis in RCC.

Fas and Fas ligand expression in pancreatic adenocarcinoma

INTRODUCTION

Fas and Fas ligand (FasL) mediate apoptosis of tumor cells in immune surveillance, and expression of FasL by tumors may mediate their counterattack on cytotoxic lymphocytes. Both proteins are expressed in most if not all pancreatic carcinoma cell lines, but their study in primary human tumors has been limited.

AIM

We performed Fas and FasL immunohistochemical staining on 81 primary pancreaticobiliary or ampullary ductal adenocarcinomas of patients in our institutional database to determine the extent and strength of staining.

METHODOLOGY

The expression of Fas and FasL was compared with regard to clinicopathologic variables, K- mutations, and immunoexpression of HER2, p21, p27, and p53.

RESULTS AND CONCLUSION

Fas was expressed in 19% of patients with strong or intermediate intensity but with variable percentages of tumor cell staining. FasL was expressed in 49% of patients, usually with diffuse expression but variable intensity. Fas expression was more common in women than men, as women had 93% of Fas-positive tumors but only 55% of Fas-negative tumors ( = 0.007), and was associated with strong HER2 expression (67% of Fas-positive versus 18% of Fas-negative patients; = 0.04). Fas expression tended to be less common in blacks (4% had Fas-positive tumors) than whites (22% had Fas-positive tumors; = 0.052). FasL expression tended to be associated with stage 4 disease at diagnosis (24% versus 0%; = 0.07). Neither Fas expression nor FasL expression was associated with survival, a circumstance suggesting that their role, if any, in contributing to the aggressiveness of these tumors is complex.

Role of stromal collagen in immunomodulation and prognosis of advanced gastric carcinoma

Although several hypotheses have been proposed explaining the mechanisms of the immune-privileged status of malignant tumors, the exact pathway is yet to be explored. Tumor stroma plays a vital role in the prognosis of cancer patients; however, the immunomodulatory impact of gastric cancer stroma has not been reported. We have evaluated the amount of stromal collagen and its impact on the infiltration of immune-competent cells into the tumor cell nest in gastric carcinoma. Tissue specimens from 84 advanced gastric carcinoma patients who had undergone a curative resection were evaluated for host immune status (CD8+ T cells), tumor stromal reaction (AZAN staining), tumor Fas ligand expression and incidence of tumor cell apoptosis (by TUNEL). The number of apoptotic tumor cells (apoptotic index [AI]) increased proportionally with an increase in the number of CD8+ T cells within the cancer cell nest (nest CD8) (p = 0.0001). Nest CD8 was inversely correlated with the amount of stromal collagen (p < 0.0001). Nest CD8 and AI became independent predictors of patient survival (p = 0.0023 and p = 0.044, respectively) in Cox's multivariate analysis. The amount of stromal collagen was found to be a significant predictor of disease relapse in univariate analysis (p = 0.0010) but not in multivariate analysis (p = 0.4729). In conclusion, increased nest CD8 produced a survival advantage by inducing tumor cell apoptosis in gastric carcinoma patients. Increased tumor stromal collagen worked as a barrier for CD8+ T-cell infiltration and might be one of the mechanisms of tumor escape from the host immune attack.