Embryologic origin of endometriosis: analysis of 101 human female fetuses.

The etiology of endometriosis, a gynecological disease characterized by the presence of endometrial glands and stroma outside the uterine cavity, is still unknown. Our research group has recently demonstrated the presence of ectopic endometrium in human female fetuses at different gestational ages. In this manuscript we describe four new cases of fetal endometriosis found among a series of 52 female fetuses analyzed at autopsy. The anatomical localization of this ectopic endometrium, and its histological and immunohistochemical characteristics are depicted. We suggest that endometriosis is caused by dislocation of primitive endometrial tissue outside the uterine cavity during organogenesis. The clinical and pathological implications of these findings are discussed.

New evidence of the presence of endometriosis in the human fetus.

The aetiology of endometriosis, a gynaecological disease defined by the histological presence of endometrial glands and stroma outside the uterine cavity, is still open to debate. Research has recently found evidence for endometriosis in human female fetuses at different gestational ages. This paper reports a new case of fetal endometriosis in a 25-week female fetus, deceased due to placental pathology, from a series of 13 female fetuses analysed at autopsy. The exact anatomical localization of this misplaced endometrium, as well as its histopathological and immunohistochemical characteristics are illustrated. The case suggests that endometriosis can be caused by dislocation of primitive endometrial tissue outside the uterine cavity during organogenesis.

Pre-natal exposure of mice to bisphenol A elicits an endometriosis-like phenotype in female offspring.

Endometriosis is a chronic gynecological disease characterized by the growth of endometrial tissue outside the uterine cavity. Exposure to endocrine disruptors during critical period of development causes long-lasting effects, being the genital system one of the targets. This study describes the effects on female genital system caused by developmental exposure to the endocrine-disrupting chemical bisphenol A (BPA) during pre- and peri-natal development in mice. To this end, timed pregnant Balb-C mice were treated from day 1 of gestation to 7 days after delivery with BPA (100, or 1000 microg/kg/day). After delivery, pups were held for 3 months; then, pelvic organs were analyzed in their entirety and livers of both pups and moms were studied for the presence of BPA. We found in the adipose tissue surrounding the genital tracts of a consistent number of treated animals, endometriosis-like structure with the presence of both glands and stroma and expressing both estrogen receptor and HOXA-10. Moreover, cystic ovaries, adenomatous hyperplasia with cystic endometrial hyperplasia and atypical hyperplasia were significantly more frequent in treated animals respect to the controls. Finally, BPA was found in the livers of exposed moms and female offspring. In conclusion, we describe for the first time an endometriosis-like phenotype in mice, elicited by pre-natal exposition to BPA. This observation may induce to thoroughly reconsider the pathogenesis and treatment of endometriosis, considering the high incidence of endometriosis and the problems caused by associated infertility.

Right ventricular cardiomyocyte apoptosis in patients with acute myocardial infarction of the left ventricular wall.

Cardiac remodeling after acute myocardial infarction (AMI) is characterized by molecular and cellular mechanisms involving both the left (LV) and right ventricular (RV) walls. Cardiomyoycte apoptosis in the peri-infarct and remote LV myocardium has a central role in cardiac remodeling. Whether apoptosis also occurs in the right ventricle of patients with ischemic heart disease has not been investigated. The aim of the present study was to investigate the presence of cardiomyocyte apoptosis in the right ventricle in patients with AMI. We assessed the number of apoptotic cardiomyocytes using multiple samplings in the LV and RV walls of 12 patients selected at autopsy who died 4 to 42 days after AMI. Five patients without cardiac disease were also selected at autopsy as controls. Apoptotic rates were calculated from the number of cardiomyocytes showing double positive staining for in situ end-labeling of DNA fragmentation (TUNEL) and for activated caspase-3. Potentially false-positive results (DNA synthesis and RNA splicing) were excluded from cell counts. The apoptotic rate in the right ventricle in patients with AMI was significantly higher than in control hearts (median 0.8%, interquartile range 0.3 to 1.0 vs median 0.01%, interquartile range 0.01 to 0.03, p <0.001). RV apoptosis significantly correlated with such parameters of global adverse remodeling as cardiac diameter to LV free wall thickness (R = +0.57, p = 0.050). RV apoptosis was significantly higher in five cases (42%) with infarct involving the ventricular septum and an adjacent small area of the RV walls (median 1.0%, interquartile range 0.8 to 2.2 vs median 0.5%, interquartile range 0.2 to 1.0, p = 0.048, p <0.001 vs controls). The association between apoptotic rate in the right ventricle and cardiac remodeling was apparent even after exclusion of cases with RV AMI involvement (R = +0.82, p = 0.023 for diameter to LV wall thickness ratio and R = -0.91, p = 0.002 for RV free wall thickness). In conclusion, patients with cardiac remodeling after AMI had a significant increase in RV apoptosis even when ischemic involvement of the RV wall was not apparent.

The ubiquitin-proteasome system and inflammatory activity in diabetic atherosclerotic plaques: effects of rosiglitazone treatment.

The role of ubiquitin-proteasome system in the accelerated atherosclerotic progression of diabetic patients is unclear. We evaluated ubiquitin-proteasome activity in carotid plaques of asymptomatic diabetic and nondiabetic patients, as well as the effect of rosiglitazone, a peroxisome proliferator-activated receptor (PPAR)-gamma activator, in diabetic plaques. Plaques were obtained from 46 type 2 diabetic and 30 nondiabetic patients undergoing carotid endarterectomy. Diabetic patients received 8 mg rosiglitazone (n = 23) or placebo (n = 23) for 4 months before scheduled endarterectomy. Plaques were analyzed for macrophages (CD68), T-cells (CD3), inflammatory cells (HLA-DR), ubiquitin, proteasome 20S activity, nuclear factor (NF)-kappaB, inhibitor of kappaB (IkappaB)-beta, tumor necrosis factor (TNF)-alpha, nitrotyrosine, matrix metalloproteinase (MMP)-9, and collagen content (immunohistochemistry and enzyme-linked immunosorbent assay). Compared with nondiabetic plaques, diabetic plaques had more macrophages, T-cells, and HLA-DR+ cells (P < 0.001); more ubiquitin, proteasome 20S activity (TNF-alpha), and NF-kappaB (P < 0.001); and more markers of oxidative stress (nitrotyrosine and O2(-) production) and MMP-9 (P < 0.01), along with a lesser collagen content and IkappaB-beta levels (P < 0.001). Compared with placebo-treated plaques, rosiglitazone-treated diabetic plaques presented less inflammatory cells (P < 0.01); less ubiquitin, proteasome 20S, TNF-alpha, and NF-kappaB (P < 0.01); less nitrotyrosine and superoxide anion production (P < 0.01); and greater collagen content (P < 0.01), indicating a more stable plaque phenotype. Similar findings were obtained in circulating monocytes obtained from the two groups of diabetic patients and cultured in the presence or absence of rosiglitazone (7.0 micromol/l). Ubiquitin-proteasome over-activity is associated with enhanced inflammatory reaction and NF-kappaB expression in diabetic plaques. The inhibition of ubiquitin-proteasome activity in atherosclerotic lesions of diabetic patients by rosiglitazone is associated with morphological and compositional characteristics of a potential stable plaque phenotype, possibly by downregulating NF-kappaB-mediated inflammatory pathways.

Patterns of tumor response in canine and feline cancer patients treated with electrochemotherapy: preclinical data for the standardization of this treatment in pets and humans.

Electrochemotherapy (ECT) is a novel anticancer therapy that is currently being evaluated in human and pet cancer patients. ECT associates the administration of an anti-tumor agent to the delivery of trains of appropriate waveforms. The increased uptake of chemotherapy leads to apoptotic death of the neoplasm thus resulting in prolonged local control and extended survival. In this paper we describe the histological features of a broad array of spontaneous tumors of companion animals receiving pulse-mediated chemotherapy. Multivariate statistical analysis of the percentage of necrosis and apoptosis in the tumors before and after ECT treatment, shows that only a high percentage of necrosis and apoptosis after the ECT treatment were significantly correlated with longer survivals of the patients (p < 0.0001 and p = 0.004, respectively). Further studies on this topic are warranted in companion animals with spontaneous tumors to identify new molecular targets for electrochemotherapy and to the develop new therapeutical protocols to be translated to humans.

Adjuvant electrochemotherapy for the treatment of incompletely resected canine mast cell tumors.

BACKGROUND: Electrochemotherapy (ECT) is a novel anticancer therapy that combines the delivery of trains of appropriate waveforms with the local administration of chemotherapy agents. The purpose of this investigation was to assess the adjuvant potentials of ECT for the treatment of incompletely excised mast cell tumors (MCT). MATERIALS AND METHODS: Twenty-eight privately-owned dogs with incompletely removed MCT were treated with intralesional bleomycin (1.5 IU/cm2) followed by the application of trains of biphasic pulses (8 pulses, 1300 V/cm, 50 + 50 micros duration, 1 Hz frequency). RESULTS: The overall response rate was 85% with a mean estimated time to recurrence of 52.76 +/- 6.5 months (range: 39.99 to 65.54 months, 95% CI). At the time of writing this report, the median survival time was not reached. Three dogs died of metastatic disease that they developed at the same time of local recurrence, one developed multiple cutaneous nodules at different locations and one with recurrence was re-treated and is currently disease-free after 22 months. No major local or systemic toxicities were noted for the duration of the study. CONCLUSION: ECT is a safe and effective therapy for incompletely excised MCTs in companion animals. Its ease of administration, lack of toxicities and low cost make it an attractive alternative to standard treatments and warrants further investigation.

Analysis of HtrA1 serine protease expression in human lung cancer.

HtrA1 is a serine protease homologue to the bacterial serine-protease HtrA, also known as DegP, a heat shock-induced envelope-associated serine protease. It has been shown that over-expression of HtrA1 in human cancer cells inhibits cell growth and proliferation in vitro and in vivo, thus, suggesting a possible role as a tumor suppressor. The expression of HtrA1 was investigated in depth by means of immunohistochemistry in a large group of human lung cancer specimens and corresponding lymph node metastases. Univariate analysis showed, that the only statistically significant correlation was found between the HtrA1 expression level detected in the primary tumors and in the lymph node metastases. This result was also confirmed when the analysis was restricted only to the cases where both the primary tumor and the autologous lymph node metastasis were available. Our data suggest that HtrA1 may be involved in lung cancer progression by targeting several molecular pathways.

Ferritin contributes to melanoma progression by modulating cell growth and sensitivity to oxidative stress.

PURPOSE: Employing an in vitro model system of human melanoma progression, we previously reported ferritin light chain (L-ferritin) gene overexpression in the metastatic phenotype. Here, we attempted to characterize the role of ferritin in the biology of human melanoma and in the progression of this disease. EXPERIMENTAL DESIGN: Starting from the LM human metastatic melanoma cell line, we engineered cell clones in which L-ferritin gene expression was down-regulated by the stable expression of a specific antisense construct. These cells were then assayed for their growth capabilities, chemoinvasive properties, and sensitivity to oxidative stress. Additionally, ferritin protein content in primary and metastatic human melanomas was determined by immunohistochemistry. RESULTS: Artificial L-ferritin down-regulation in the LM cells strongly inhibited proliferation and chemoinvasion in vitro and cell growth in vivo. In addition, L-ferritin down-regulated cells displayed enhanced sensitivity to oxidative stress and to apoptosis. Concurrently, immunohistochemical analysis of a human melanoma tissue array revealed that ferritin expression level in metastatic lesions was significantly higher (P < 0.0001) than in primary melanomas. Furthermore, ferritin expression was constantly up-regulated in autologous lymph node melanoma metastases when compared with the respective primary tumors in a cohort of 11 patients. CONCLUSIONS: These data suggest that high ferritin expression can enhance cell growth and improve resistance to oxidative stress in metastatic melanoma cells by interfering with their cellular antioxidant system. The potential significance of these findings deserves to be validated in a clinical setting.

The HtrA1 serine protease is down-regulated during human melanoma progression and represses growth of metastatic melanoma cells.

Differential gene expression of cell lines derived from a malignant melanoma or its autologous lymph node metastasis using cDNA arrays indicated down-regulation of PRSS11, a gene encoding the serine protease HtrA1, a homolog of the Escherichia coli protease HtrA, in the metastatic line. Stable PRSS11 overexpression in the metastatic cell line strongly inhibited proliferation, chemoinvasion and Nm23-H1 protein expression in vitro, as well as cell growth in vivo in nu/nu mice. A polyclonal anti-HtrA1 serum demonstrated a significantly higher expression in primary melanomas when compared to unrelated metastatic lesions in a human melanoma tissue array, and down-modulation of HtrA1 expression in autologous lymph node melanoma metastases in seven out of 11 cases examined. These results suggest that down-regulation of PRSS11 and HtrA1 expression may represent an indicator of melanoma progression.

Persistent infarct-related artery occlusion is associated with an increased myocardial apoptosis at postmortem examination in humans late after an acute myocardial infarction.

BACKGROUND: Myocardial apoptosis persists beyond the acute phases of acute myocardial infarction (AMI) and is associated with left ventricular (LV) remodeling. Infarct-related artery (IRA) patency is considered a favorable prognostic factor after AMI and may be associated with more favorable LV remodeling because of reduced apoptosis at the site of AMI. The aim of this study was to assess the influence of IRA status on apoptotic rate (AR) in the hearts of subjects dying late after AMI. METHODS AND RESULTS: We used colocalization for in situ end-labeling of DNA fragmentation and immunohistochemistry for caspase-3 to calculate the AR at time of death (12 to 62 days after AMI) in 16 hearts with persistently occluded IRAs and in 8 hearts with patent IRAs. No significant differences were found when comparing the clinical characteristics of the 2 groups. Occluded IRA was associated with significantly higher AR at site of infarction (25.8% [interquartile range 20.9% to 28.5%] versus 2.3% [interquartile range 0.6% to 5.0%], P<0.001). This strong correlation between IRA occlusion and AR remained statistically significant even after correction for clinical characteristics such as sex, age, history of previous additional AMI or heart failure, transmural AMI, anterior AMI, fibrinolytic treatment, time from AMI to death, trauma as cause of death, and multivessel coronary disease (P=0.003). CONCLUSIONS: A significantly higher AR was associated with persistent IRA occlusion late post-AMI. These data may suggest that the post-AMI benefits observed with a patent IRA (the "open-artery hypothesis") may in part be due to reduced myocardial apoptosis.

Widespread myocardial inflammation and infarct-related artery patency.

BACKGROUND: Diffuse coronary vascular inflammation is associated with acute coronary syndromes. However, it is unknown whether inflammation also occurs within the myocardium. Therefore, this study was aimed at assessing the presence of activated cells in unaffected remote myocardium of patients with acute myocardial infarction (AMI), in comparison to the peri-infarct region from the same cases, and in comparison to myocardial specimens from control hearts. METHODS AND RESULTS: Sixteen patients dying 1 to 12 weeks after AMI and 16 control subjects were selected at autopsy. Myocardial specimens were taken at remote unaffected viable regions and at peri-infarct regions in cases with AMI. Confocal microscopy was performed to measure the number of activated cells (DR+), T-lymphocytes (CD3+), and activated T-lymphocytes (CD3+/DR+). Activated cells and activated T-lymphocytes were found in remote unaffected regions in 11 of 16 cases (69%), in peri-infarct zone in all cases (100%), and in none of the control hearts (0%, P<0.001 versus others). A greater myocardial inflammatory burden in remote regions but not in peri-infarct regions was associated with persistent infarct-related artery occlusion (P<0.05). CONCLUSIONS: This study for the first time shows the presence of activated T-lymphocytes in remote unaffected myocardial regions in approximately two thirds of patients with recent AMI. Because these cells are associated with persistent infarct-related artery occlusion, our data may suggest that an antigenic stimulus present also in the myocardium triggers an immune response that may be critical to precipitate artery occlusion.

Expression of angiogenic factors during acute coronary syndromes in human type 2 diabetes.

Inadequate angiogenic response to ischemia in diabetic myocardium could result in poor collateral formation. Because hypoxia-inducible factor (HIF)-1alpha is a transcriptional activator of vascular endothelial growth factor (VEGF) and is critical for initiating angiogenic responses to hypoxia, we investigated the expression of HIF-1alpha and VEGF in specimens of human heart tissue to elucidate the molecular responses to myocardial ischemia in diabetic patients during unstable angina. Moreover, accumulation of a marker of protein nitration nitrotyrosine, as well as the superoxide anion (O(2)(-)) levels and inducible nitric oxide synthase (iNOS), were evaluated. Ventricular biopsy specimens from 15 type 2 diabetic and 14 nondiabetic patients presenting with unstable angina (ischemic group) and from 20 patients (11 type 2 diabetic and 9 nondiabetic patients) who underwent coronary bypass surgery without angina within the preceding 10 days (control group) were collected during coronary bypass surgery. Nondiabetic patients had higher HIF-1alpha and VEGF expressions compared with diabetic patients (P < 0.001). As compared with nondiabetic specimens, diabetic specimens showed higher levels of both iNOS mRNA and protein levels (P < 0.001) associated with the highest tissue levels of nitrotyrosine and O(2)(-) (P < 0.001). Diabetes is associated with increased myocardial tissue levels of iNOS, O(2)(-), and nitrotyrosine and reduced expression of myocardial angiogenesis factors during ischemia.

Increased myocardial apoptosis in patients with unfavorable left ventricular remodeling and early symptomatic post-infarction heart failure.

OBJECTIVES: The purpose of this study was to evaluate a potential correlation between apoptotic rate (AR), post-infarction left ventricular (LV) remodeling, and clinical characteristics in subjects who died late (>or=10 days) after an acute myocardial infarction (AMI) with evidence of persistent occlusion of the infarct-related artery at autopsy. BACKGROUND: Apoptosis contributes to myocardiocyte loss in cardiac disease and may have a pathophysiologic role in post-infarction LV remodeling. METHODS: The AR was calculated at the site of infarction and in remote unaffected LV regions, using co-localization of in situ end labeling for deoxyribonucleic acid fragmentation and immunohistochemistry for caspase-3, in 14 subjects who died within two months after AMI. Correlation between AR and clinical characteristics such as age, site of AMI, transmural extension, multivessel coronary disease, and signs and/or symptoms of heart failure (HF), at the time of initial hospitalization for AMI or subsequently before death, was assessed using non-parametric statistical tests. Parameters of LV remodeling including diameters, free wall thickness, diameter-to-wall-thickness ratio, and mass were measured at gross examination at autopsy. Values are expressed as median (interquartile range). RESULTS: Among clinical variables, early symptomatic post-infarction HF (9 cases, 64%) was associated with nearly fourfold increased AR at the site of infarction (26.2% [24.5% to 28.8%] vs. 6.4% [1.9% to 13.3%], p = 0.001). Moreover, AR both at the site of infarction and in unaffected regions was significantly correlated with parameters of progressive LV remodeling (p < 0.05). CONCLUSIONS: Our data show that in patients dying >or=10 days after AMI, myocardial apoptosis is strongly associated with and may be a major determinant of unfavorable LV remodeling and early symptomatic post-infarction HF.

Loss of pRb2/p130 expression is associated with unfavorable clinical outcome in lung cancer.

Altered expression of cell cycle regulators represents a frequent event in both small cell and non-small cell lung cancer (NSCLC). Despite several studies that reported involvement of tumor suppressor genes, such as p53 and pRb, in the development and progression of lung cancer, contrasting opinions exist about the prognostic role of this protein in this neoplasm. We developed an immunohistochemical assay suitable for the detection of pRb2/p130, the last discovered member of the retinoblastoma gene family, on formalin-fixed and paraffin-embedded sections. We evaluated the immunohistochemical expression of pRb2/p130 in 135 lung cancer specimens, and performed Western blot analysis in a subset of 30 corresponding tumor lysates. A high correlation between immunohistochemical data and Western blot results (P = 0.0004) was found. We statistically analyzed the relationship between overall survival (OS) time and pRb2/p130 expression according to the different histological types in 105 patients. We did not find any correlation between pRb2/p130 expression and OS in small cell lung cancers, whereas in NSCLCs a direct relationship between pRb2 and OS was found in both adenocarcinoma (P = 0.0002) and squamous cell carcinoma (P = 0.0002) histotypes. According to univariate analysis, pRb2/p130 was a prognostic factor of which the lost or reduced expression correlated with a shorter OS (P < 0.0000). At multivariate analysis, pRb2/p130 expression was an independent predictor of OS (P = 0.0001) when considered together with histotype. This study demonstrates for the first time the potential independent prognostic value of pRb2/p130 expression on formalin-fixed, paraffin-embedded sections from lung cancer patients. pRb2/p130 immunoreactivity can be used to predict OS in patients with NSCLC and, therefore, may represent a new prognostic marker.

A case of granulomatous skin lesions caused by Mycobacterium marinum in the Campania region.

The diagnosis of cutaneous Mycobacterium marinum infection is frequently presumptive, as detection by conventional methods is difficult. We describe a patient with granulomatous skin lesions on the right dorsal hand and forearm. Histological examinations were presumptive for mycobacterium lesions. We identified Mycobacterium marinum directly in the patient's lesional skin biopsy combining polymerase chain reaction (PCR) amplification using Mycobacterium genus-specific primers, and subsequent restriction enzyme analysis enabling identification to the species level. The symptoms were no longer present after specific therapy, thereby confirming the initial diagnosis.

Distribution of the serine protease HtrA1 in normal human tissues.

The human HtrA family of proteases consists of three members: HtrA1, HtrA2, and HtrA3. In bacteria, the chief role of HtrA is recognition and degradation of misfolded proteins in the periplasm, combining a dual activity of chaperone and protease. In humans, the three HtrA homologues appear to be involved in diverse functions such as cell growth, apoptosis, allergic reactions, fertilization, control of blood pressure, and blood clotting. Previous studies using RNA blot hybridization have shown that the expression of HtrA1 is ubiquitous in normal human tissues. Here we show by immunohistochemistry (IHC) that HtrA1 is widely expressed, although different tissue distributions and/or levels of expression were detected in the different tissues examined. In particular, high to medium HtrA1 expression was detected in mature layers of epidermis, in secretory breast epithelium, in liver, and in kidney tubules of cortex, in concordance with its secretory properties. Furthermore, we show a higher protein expression level in the epithelium of proliferative endometrium, in contrast to epithelium of secretory endometrium, which is almost completely negative for this protein. This suggests a possible role for HtrA1 in the modulation of tissue activity in this organ. The various expression levels in human tissues indicate several possible roles for HtrA1 in different cell types.

Pattern of expression of HtrA1 during mouse development.

The human HtrA family of proteases consists of four members: HtrA1, HtrA2, HtrA3, and HtrA4. In humans the four HtrA homologues appear to be involved in several important functions such as cell growth, apoptosis, and inflammatory reactions, and they control cell fate via regulated protein metabolism. In previous studies it was shown that the expression of HtrA1 was ubiquitous in normal adult human tissues. Here we examined the expression of HtrA1 protein and its corresponding mRNA during mouse embryogenesis using Northern blotting hybridization, RT-PCR, and immunohistochemical staining analyses. Our results indicate that HtrA1 is expressed in a variety of tissues in mouse embryos. Furthermore, this expression is regulated in a spatial and temporal manner. Relatively low levels of HtrA1 mRNA are detected in embryos at the beginning of organogenesis (E8), and the levels of expression increase during late organogenesis (E14-E19). Our results show that HtrA1 was expressed during embryonic development in specific areas where signaling by TGFbeta family proteins plays important regulatory roles. The expression of HtrA1, documented both at mRNA and protein levels by RT-PCR and immunohistochemistry in the developing nervous system, is consistent with a possible role of this protein both in dividing and postmitotic neurons, possibly via its documented inhibitory effects on TGFbeta proteins. An exhaustive knowledge of the different cell- and tissue-specific patterns of expression of HtrA1 in normal mouse embryos is essential for a critical evaluation of the exact role played by this protein during development.

Expression of surface protein receptors in lung cancer.

Cell adhesion is a basic count in inter- and intracellular communication and plays an important role in tumor progression. In this study, the expression of E-selectin, ICAM-1 and VCAM-1 were evaluated by means of immunohistochemistry in a group of 153 lung cancer specimens. E-selectin immunoreactivity was localized mostly on endothelial cell venules and capillaries with an average staining intensity of 75% of cells in the NSCLC, while in SCLC the intensity of the staining was 69%. The staining pattern for ICAM-1 reached an average intensity of 57%, in both NSCLC and SCLC. Finally, VCAM-1 immunoreactivity was detected only in NSCLC with an average intensity of 12% on endothelial cell venules and capillaries. This study provides a contribution towards the understanding of the basic mechanisms of cell adhesion in lung cancer progression.

Analysis of Fas (Apo-1/CD95) expression in non-small cell lung cancer.

Defects in the apoptotic pathway represent a critical element in the progression of neoplastic disease and may also concur to determine treatment efficacy at the cellular level. Fas (Apo-1/CD95) is a cell-surface receptor involved in cell death signaling. In this study we analyzed, by immunohistochemistry, the expression of Fas protein in a group of 68 NSCLC (non-small cell lung cancer) specimens. Statistical analyses did not show any significant relationship between Fas immunohistochemical expression and clinical parameters of lung cancer patients, except for nodal status. Our data do not support the use of Fas as a molecular prognostic role in NSCLC. On the other hand, considering the role of the Fas-pathway in chemotherapy-induced apoptosis, further studies are required to analyze the potential value of Fas expression in predicting the response of NSCLC patients to chemotherapy.