940 resultados para Epithelial Tumors


Relevância:

30.00% 30.00%

Publicador:

Resumo:

Epithelial (E)-cadherin and its associated cytoplasmic proteins (α-, β-, and γ-catenins) are important mediators of epithelial cell–cell adhesion and intracellular signaling. Much evidence exists suggesting a tumor/invasion suppressor role for E-cadherin, and loss of expression, as well as mutations, has been described in a number of epithelial cancers. To investigate whether E-cadherin gene (CDH1) mutations occur in colorectal cancer, we screened 49 human colon carcinoma cell lines from 43 patients by single-strand conformation polymorphism (SSCP) analysis and direct sequencing. In addition to silent changes, polymorphisms, and intronic variants in a number of the cell lines, we detected frameshift single-base deletions in repeat regions of exon 3 (codons 120 and 126) causing premature truncations at codon 216 in four replication-error-positive (RER+) cell lines (LS174T, HCT116, GP2d, and GP5d) derived from 3 patients. In LS174T such a mutation inevitably contributes to its lack of E-cadherin protein expression and function. Transfection of full-length E-cadherin cDNA into LS174T cells enhanced intercellular adhesion, induced differentiation, retarded proliferation, inhibited tumorigenicity, and restored responsiveness to the migratory effects induced by the motogenic trefoil factor 2 (human spasmolytic polypeptide). These results indicate that, although inactivating E-cadherin mutations occur relatively infrequently in colorectal cancer cell lines overall (3/43 = 7%), they are more common in cells with an RER+ phenotype (3/10 = 30%) and may contribute to the dysfunction of the E-cadherin–catenin-mediated adhesion/signaling system commonly seen in these tumors. These results also indicate that normal E-cadherin-mediated cell adhesion can restore the ability of colonic tumor cells to respond to trefoil factor 2.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Serine proteases of the chymotrypsin fold are of great interest because they provide detailed understanding of their enzymatic properties and their proposed role in a number of physiological and pathological processes. We have been developing the macromolecular inhibitor ecotin to be a “fold-specific” inhibitor that is selective for members of the chymotrypsin-fold class of proteases. Inhibition of protease activity through the use of wild-type and engineered ecotins results in inhibition of rat prostate differentiation and retardation of the growth of human PC-3 prostatic cancer tumors. In an effort to identify the proteases that may be involved in these processes, reverse transcription–PCR with PC-3 poly(A)+ mRNA was performed by using degenerate oligonucleotide primers. These primers were designed by using conserved protein sequences unique to chymotrypsin-fold serine proteases. Five proteases were identified: urokinase-type plasminogen activator, factor XII, protein C, trypsinogen IV, and a protease that we refer to as membrane-type serine protease 1 (MT-SP1). The cloning and characterization of the MT-SP1 cDNA shows that it encodes a mosaic protein that contains a transmembrane signal anchor, two CUB domains, four LDLR repeats, and a serine protease domain. Northern blotting shows broad expression of MT-SP1 in a variety of epithelial tissues with high levels of expression in the human gastrointestinal tract and the prostate. A His-tagged fusion of the MT-SP1 protease domain was expressed in Escherichia coli, purified, and autoactivated. Ecotin and variant ecotins are subnanomolar inhibitors of the MT-SP1 activated protease domain, suggesting a possible role for MT-SP1 in prostate differentiation and the growth of prostatic carcinomas.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Injury, inflammation, or resection of the small intestine results in severe compromise of intestinal function. Nevertheless, therapeutic strategies for enhancing growth and repair of the intestinal mucosal epithelium are currently not available. We demonstrate that nude mice bearing subcutaneous proglucagon-producing tumors exhibit marked proliferation of the small intestinal epithelium. The factor responsible for inducing intestinal proliferation was identified as glucagon-like peptide 2 (GLP-2), a 33-aa peptide with no previously ascribed biological function. GLP-2 stimulated crypt cell proliferation and consistently induced a marked increase in bowel weight and villus growth of the jejunum and ileum that was evident within 4 days after initiation of GLP-2 administration. These observations define a novel biological role for GLP-2 as an intestinal-derived peptide stimulator of small bowel epithelial proliferation.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The potent transforming activity of membrane-targeted Raf-1 (Raf-CAAX) suggests that Ras transformation is triggered primarily by a Ras-mediated translocation of Raf-1 to the plasma membrane. However, whereas constitutively activated mutants of Ras [H-Ras(61L) and K-Ras4B(12V)] and Raf-1 (DeltaRaf-22W and Raf-CAAX) caused indistinguishable morphologic and growth (in soft agar and nude mice) transformation of NIH 3T3 fibroblasts, only mutant Ras caused morphologic transformation of RIE-1 rat intestinal cells. Furthermore, only mutant Ras-expressing RIE-1 cells formed colonies in soft agar and developed rapid and progressive tumors in nude mice. We also observed that activated Ras, but not Raf-1, caused transformation of IEC-6 rat intestinal and MCF-10A human mammary epithelial cells. Although both Ras- and DeltaRaf-22W-expressing RIE-1 cells showed elevated Raf-1 and mitogen-activated protein (MAP) kinase activities, only Ras-transformed cells produced secreted factors that promoted RIE-1 transformation. Incubation of untransformed RIE-1 cells in the presence of conditioned medium from Ras-expressing, but not DeltaRaf-22W-expressing, cells caused a rapid and stable morphologic transformation that was indistinguishable from the morphology of Ras-transformed RIE-1 cells. Thus, induction of an autocrine growth mechanism may distinguish the transforming actions of Ras and Raf. In summary, our observations demonstrate that oncogenic Ras activation of the Raf/MAP kinase pathway alone is not sufficient for full tumorigenic transformation of RIE-1 epithelial cells. Thus, Raf-independent signaling events are essential for oncogenic Ras transformation of epithelial cells, but not fibroblasts.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

mac25, the subject of this report, was selected by the differential display of mRNA method in a search for genes overexpressed in senescent human mammary epithelial cells. mac25 had previously been cloned as a discrete gene, preferentially expressed in normal, leptomeningial cells compared with meningioma tumors. mac25 is another member of the insulin growth factor-binding protein (IGFBP) family. Insulin-like growth factors are potent mitogens for mammary epithelial cells, and the IGFBPs have been shown to modulate this mitogenic activity. We report here that mac25, unlike most IGFBPs, is down-regulated at the transcription level in mammary carcinoma cell lines, suggesting a tumor-suppressor role. The gene was mapped to chromosome 4q12. We found that mac25 accumulates in senescent cells and is up-regulated in normal, growing mammary epithelial cells by all-trans-retinoic acid or the synthetic retinoid fenretinide. These findings suggest that mac25 may be a downstream effector of retinoid chemoprevention in breast epithelial cells and that its tumor-suppressive role may involve a senescence pathway.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Objective. To document symptoms associated with borderline, early and advanced ovarian cancer and identify personal characteristics associated with early versus late diagnosis. Methods. Information concerning symptoms and diagnosis history was available from 811 women with ovarian cancer who took part in an Australian case–control study in the early 1990s. Women were classified into three groups for comparison based on their diagnosis: borderline, early (stage I–II) and advanced (stage III–IV) invasive cancer. Results. Sixteen percent of women with borderline tumors, 7% with early cancer and 4% with advanced cancer experienced no symptoms before diagnosis (P < 0.0001). Among women with symptoms, abdominal pain (44%) or swelling (39%) were most frequently reported; an abdominal mass (12%) and gynecological symptoms (12%) were less common. Compared to advanced stage cancer, women with early stage cancer were more likely to report an abdominal mass or urinary symptoms but less likely to report gastrointestinal problems or general malaise. General malaise and ‘other’ symptoms were least common in borderline disease. Older women, and those with higher parity or a family history of breast or ovarian cancer, were more likely to be diagnosed at an advanced stage of disease. Conclusions. Women who experience persistent or recurrent abdominal symptoms, particularly swelling and/or pain should be encouraged to seek medical attention and physicians should be alert to the possibility of ovarian cancer even in the absence of an abdominal mass. Further information about the prevalence of these symptoms in the general population is essential to assist physicians in patient management.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The majority of epithelial ovarian carcinomas are of serous subtype, with most women presenting at an advanced stage. Approximately 70% respond to initial chemotherapy but eventually relapse. We aimed to find markers of treatment response that might be suitable for routine use, using the gene expression profile of tumor tissue. Thirty one women with histologically-confirmed late-stage serous ovarian cancer were classified into 3 groups based on response to treatment (nonresponders, responders with relapse less than 12 months and responders with no relapse within 12 months). Gene expression profiles of these specimens were analyzed with respect to treatment response and survival (minimum 36 months follow-up). Patients' clinical features did not correlate with prognosis, or with specific gene expression patterns of their tumors. However women who did not respond to treatment could be distinguished from those who responded with no relapse within 12 months based on 34 gene transcripts (p < 0.02). Poor prognosis was associated with high expression of inhibitor of differentiation-2 (ID2) (p = 0.001). High expression of decorin (DCN) and ID2 together was strongly associated with reduced survival (p = 0.003), with an estimated 7-fold increased risk of dying (95% CI 1.9-29.6; 14 months survival) compared with low expression (44 months). Immunohistochemical analysis revealed both nuclear and cytoplasmic distribution of ID2 in ovarian tumors. High percentage of nuclear staining vas associated with poor survival, although not statistically significantly. In conclusion, elevated expression of ID2 and DCN was significantly associated with poor prognosis in a homogeneous group of ovarian cancer patients for whom survival could not be predicted from clinical factors. (c) 2006 Wiley-Liss, Inc.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Cancer research and development of targeting agents in this field is based on robust studies using preclinical models. The failure rate of standardized treatment approaches for several solid tumors has led to the urgent need to fine-tune more sophisticated and faithful preclinical models able to recapitulate the features of in vivo human tumors, with the final aim to shed light on new potential therapeutic targets. Epithelial Ovarian Cancer (EOC) serous histotype (HGSOC) is one of the most lethal diseases in women due to its high aggressiveness (75% of patients diagnosed at FIGO III-IV state) and poor prognosis (less of 50% in 5 years), whose therapy often fails as chemoresistance sets in. This thesis aimed at using the novel perfusion-based bioreactor U-CUP that provides direct perfusion throughout the tumor tissue seeking to obtain an EOC 3D ex vivo model able to recapitulate the features of the original tumor including the tumor microenvironment and maintaining its cellular heterogeneity. Moreover, we optimized this approach so that it can be successfully applied to slow-frozen tumoral tissues, further extending the usefulness of this tool. We also investigated the effectiveness of Plasma Activated Ringer’s Lactate solution (PA-RL) against Epithelial Ovarian Cancer (EOC) serous histotype in both 2D and 3D cultures using ex-vivo specimens from HGSOC patients. We propose PA-RL as a novel therapy with local intraperitoneal administration, which could act on primary or metastatic ovarian tumors inducing a specific cancer cell death with reduced damage on the surrounding healthy tissues.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Desmoid tumor (DT) is a common manifestation of Gardner's Syndrome (GS), although it is a rare condition in the general population. DT in patients with GS is usually located in the abdominal wall and/or intra-abdominal cavity. We report a case of a 32 years-old female patient with familial adenomatous polyposis (FAP), who was already submitted to total colectomy and developed multiple DT, located in the abdominal wall and in the left breast. The patient underwent several surgical procedures, with a multidisciplinary team of surgeons. Wide surgical resections of the left breast and the abdominal wall tumors were performed in separate steps. Polypropylene mesh reconstruction and muscle flaps were needed to cover the defects of the thoracic and abdominal walls. After partial necrosis of the adipose-cutaneous flap in the abdomen that required a new skin graft, she had a satisfactory outcome with complete healing of the surgical incisions. DT is frequent in GS, however, breast localization is very rare, with few cases reported in the literature. Recurrence of DT is not negligible, even after a wide surgical resection. GS patients must be followed up closely, and clinical examination, associated with imaging studies, should be performed to detect any signs of tumor. DT represents one of the most significant causes of the morbidity and mortality that affects FAP patients following colectomy. In general, the surgical procedures to excise DT are highly complex, requiring a multidisciplinary team.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The mechanism underlying castration-induced prostate regression, which is a classical physiological concept translated into the therapeutic treatment of advanced prostate cancer, involves epithelial cell apoptosis. In searching for events and mechanisms contributing to prostate regression in response to androgen modulation, we have frequently observed the collective deletion of epithelial cells. This work was undertaken to characterize this phenomenon hereafter named desquamation and to verify its presence after 17β-estradiol (E2) administration. Electron microscopy revealed that the desquamating cells had preserved cell-cell junctions and collapsed nuclear contents. The TUNEL reaction was negative for these cells, which were also negative for cleaved caspases-8, -9, -3 and nuclear apoptosis-inducing factor. Detailed analyses revealed that the condensed chromatin was first affected detaching from the nuclear lamina, which was observable after lamin A immunohistochemistry, suggesting the lack of lamin A degradation. A search in animals treated with supraphysiological E2 employed as an alternative anti-androgen treatment revealed no desquamation. The combined treatment (Cas + E2 group) caused changes particular to each treatment, including desquamation. In conclusion, desquamation appeared as a novel phenomenon contributing to collective prostate epithelial cell deletion, distinct from the classical castration-induced apoptosis and particular to the androgen deprivation resulting from surgical castration, and should be considered as part of the mechanisms promoting organ regression.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The purpose of this study was to assess the efficacy and reproducibility of the cytologic diagnosis of salivary gland tumors (SGTs) using fine-needle aspiration cytology (FNAC). The study aimed to determine diagnostic accuracy, sensitivity, and specificity and to evaluate the extent of interobserver agreement. We retrospectively evaluated SGTs from the files of the Division of Pathology at the Clinics Hospital of São Paulo and Piracicaba Dental School between 2000 and 2006. We performed cytohistologic correlation in 182 SGTs. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were 94%, 100%, 100%, 100%, and 99%, respectively. The interobserver cytologic reproducibility showed significant statistical concordance (P < .0001). FNAC is an effective tool for performing a reliable preoperative diagnosis in SGTs and shows high diagnostic accuracy and consistent interobserver reproducibility. Further FNAC studies analyzing large samples of malignant SGTs and reactive salivary lesions are needed to confirm their accuracy.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Most epidemiological studies concerning differentiated thyroid cancers (DTC) indicate an increasing incidence over the last two decades. This increase might be partially explained by the better access to health services worldwide, but clinicopathological analyses do not fully support this hypothesis, indicating that there are carcinogenetic factors behind this noticeable increasing incidence. Although we have undoubtedly understood the biology and molecular pathways underlying thyroid carcinogenesis in a better way, we have made very little progresses in identifying a risk profile for DTC, and our knowledge of risk factors is very similar to what we knew 30-40 years ago. In addition to ionizing radiation exposure, the most documented and established risk factor for DTC, we also investigated the role of other factors, including eating habits, tobacco smoking, living in a volcanic area, xenobiotics, and viruses, which could be involved in thyroid carcinogenesis, thus, contributing to the increase in DTC incidence rates observed.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Pituitary macroadenomas are rare intracranial tumors. In a few cases, they may present aggressive behavior and invade the sphenoid sinus and nasal cavity, causing unusual symptoms. In this paper, we report an atypical case of pituitary adenoma presenting as a nasal mass. The patient was a 44-year-old woman who had had amenorrhea and galactorrhea for ten months, with associated nasal obstruction, macroglossia and acromegaly. Both growth hormone and prolactin levels were increased. Magnetic resonance imaging showed a large mass originating from the lower surface of the pituitary gland, associated with sella turcica erosion and tumor extension through the sphenoid sinus and nasal cavity. Histopathological analysis demonstrated a chromophobe pituitary adenoma with densely packed rounded epithelial cells, with some atypias and rare mitotic figures. There was no evidence of metastases. Macroadenoma invading the nasal cavity is a rare condition and few similar cases have been reported in the literature. This study contributes towards showing that tumor extension to the sphenoid sinus and nasopharynx needs to be considered and investigated in order to make an early diagnosis when atypical symptoms like nasal obstruction are present.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

During the last 30 years many advances have been made in kidney tumor pathology. In 1981, 9 entities were recognized in the WHO Classification. In the latest classification of 2004, 50 different types have been recognized. Additional tumor entities have been described since and a wide variety of prognostic parameters have been investigated with variable success; however, much attention has centered upon the importance of features relating to both stage and grade. The International Society of Urological Pathology (ISUP) recommends after consensus conferences the development of reporting guidelines, which have been adopted worldwide ISUP undertook to review all aspects of the pathology of adult renal malignancy through an international consensus conference to be held in 2012. As in the past, participation in this consensus conference was restricted to acknowledged experts in the field.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Iranian propolis is a natural product of honeybees that has significant and varied anti-cancer benefits. The present study was designed to investigate the protective effects of Iranian propolis on gastric tissue carcinogenesis in an animal model.  Propolis samples were collected from Hamadan and Taleghan districts of Iran, followed by ultra performance liquid chromatography mass spectrometry analysis. Fifty-five rats were divided into three groups; control, Taleghan propolis and Hamadan propolis. All the animals received N-methyl-N-nitro-N-nitrosoguanidine (MNNG, 100 μg/ml) in drinking water ad libitum for 34 weeks. In the treated groups, nutrition with propolis was started two weeks before MNNG administration. At the end of the study, the entire gastrointestinal tract was scrutinized for tumors, and the rest of the body was assessed for metastatic deposits.  Results indicated that the incidence and number of tumors were significantly decreased by propolis in comparison with the control group (P < 0.05). The nuclear/cytoplasmic ratio, epithelial stratification, nuclear dispolarity, structural abnormality, and Beta-catenin and Bcl-2 proteins expression were significantly reduced in the propolis group compared to the control group (P < 0.05). In addition, Bax protein expression was significantly increased in the propolis group in comparison with the control group (P < 0.05).  The present study demonstrated the potential chemoprotective effects of the Iranian propolis against gastric cancer in a typical animal model. The results provide evidence for the hypothesis that Iranian propolis may exert a chemoprotective effect on MNNG-initiated gastric cancer through inhibition of cell proliferation and apoptosis induction.