RESUMO
Micro RNAs (miRs) are small non-coding RNAs aberrantly expressed in human tumors. Here, we aim to identify miRs whose deregulated expression leads to the activation of oncogenic pathways in human gastric cancers (GCs). Thirty nine out of 123 tumoral and matched uninvolved peritumoral gastric specimens from three independent European subsets of patients were analyzed for the expression of 851 human miRs using Agilent Platform. The remaining 84 samples were used to validate miRs differentially expressed between tumoral and matched peritumoral specimens by qPCR. miR-204 falls into a group of eight miRs differentially expressed between tumoral and peritumoral samples. Downregulation of miR-204 has prognostic value and correlates with increased staining of Bcl-2 protein in tumoral specimens. Ectopic expression of miR-204 inhibited colony forming ability, migration and tumor engraftment of GC cells. miR-204 targeted Bcl-2 messenger RNA and increased responsiveness of GC cells to 5-fluorouracil and oxaliplatin treatment. Ectopic expression of Bcl-2 protein counteracted miR-204 pro-apoptotic activity in response to 5-fluorouracil. Altogether, these findings suggest that modulation of aberrant expression of miR-204, which in turn releases oncogenic Bcl-2 protein activity might hold promise for preventive and therapeutic strategies of GC.
Assuntos
MicroRNAs/genética , Proteínas Proto-Oncogênicas c-bcl-2/genética , Neoplasias Gástricas/genética , Animais , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Fluoruracila/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Camundongos , Camundongos Nus , MicroRNAs/metabolismo , Compostos Organoplatínicos/farmacologia , Oxaliplatina , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Neoplasias Gástricas/tratamento farmacológico , Neoplasias Gástricas/metabolismo , Regulação para CimaRESUMO
BACKGROUND: This multi-centre phase II clinical trial is the first prospective evaluation of radioembolisation of patients with colorectal liver metastases (mCRC) who failed previous oxaliplatin- and irinotecan-based systemic chemotherapy regimens. METHODS: Eligible patients had adequate hepatic, haemopoietic and renal function, and an absence of major hepatic vascular anomalies and hepato-pulmonary shunting. Gastroduodenal and right gastric arteries were embolised before hepatic arterial administration of yttrium-90 resin microspheres (median activity, 1.7 GBq; range, 0.9-2.2). RESULTS: Of 50 eligible patients, 38 (76%) had received > or =4 lines of chemotherapy. Most presented with synchronous disease (72%), >4 hepatic metastases (58%), 25-50% replacement of total liver volume (60%) and bilateral spread (70%). Early and intermediate (>48 h) WHO G1-2 adverse events (mostly fever and pain) were observed in 16 and 22% of patients respectively. Two died due to renal failure at 40 days or liver failure at 60 days respectively. By intention-to-treat analysis using Response Evaluation Criteria in Solid Tumours, 1 patient (2%) had a complete response, 11 (22%) partial response, 12 (24%) stable disease, 22 (44%) progressive disease; 4 (8%) were non-evaluable. Median overall survival was 12.6 months (95% CI, 7.0-18.3); 2-year survival was 19.6%. CONCLUSION: Radioembolisation produced meaningful response and disease stabilisation in patients with advanced, unresectable and chemorefractory mCRC.
Assuntos
Neoplasias Colorretais/patologia , Neoplasias Hepáticas/radioterapia , Neoplasias Hepáticas/secundário , Radioisótopos de Ítrio/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Terapia Combinada , Embolização Terapêutica/métodos , Feminino , Artéria Hepática , Humanos , Contagem de Leucócitos , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/mortalidade , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Qualidade de Vida , Análise de Sobrevida , Tomografia Computadorizada por Raios X , Radioisótopos de Ítrio/administração & dosagem , Radioisótopos de Ítrio/efeitos adversosRESUMO
Young people (40 years of age) with colorectal cancer (CRC) represent a distinct subgroup with more aggressive disease behaviour compared to older patients. We evaluate whether p53 and bcl-2 could be useful in identifying young patients at higher risk of tumour progression. We reviewed 1340 CRC patients with 58 patients 40 years (4.2%). They had more frequent moderately or poorly differentiated mucinous adenocarcinomas (26% versus 12.3%, p=0.03); higher advanced stage at diagnosis; shorter 5-year overall survival (49.8% versus 71%; p=0.02); more frequent p53 positive (89.8% versus 72.6%, p<0.05) and bcl-2 negative (88.0% versus 66.2%, p<0.05) tumours; no difference in DNA content or proliferation indexes. Moreover, p53+ and bcl-2- resulted in being independent predictors of survival with shorter survival for the p53+/bcl-2- patients. Combining p53 and bcl-2, we could identify young CRC patients at higher risk of progression, who probably require development of a more sophisticated therapeutic approach based on identification of predictive factors.
Assuntos
Neoplasias Colorretais/mortalidade , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Apoptose/fisiologia , Transformação Celular Neoplásica/patologia , Distribuição de Qui-Quadrado , Neoplasias Colorretais/patologia , Feminino , Humanos , Imuno-Histoquímica , Estimativa de Kaplan-Meier , Antígeno Ki-67/metabolismo , Masculino , Pessoa de Meia-IdadeRESUMO
AIM: Survivin is a member of the inhibitors of apoptosis (IAP) gene family that acts through pathways different from those involving the bcl-2 family. Largely undetectable in normal adult tissues, survivin is deregulated in most human cancers including non-small-cell lung cancer (NSCLC) and may represent a tumor marker with prognostic and therapeutic implications. Aim of our study was to determine the prognostic role of survivin as an apoptosis-related biomarker in a series of resected NSCLC patients. METHODS: A retrospective series of resected NSCLC patients were retrieved from the files of the Regina Elena National Cancer Institute. Survivin was detected by immunohistochemistry (IHC) using a polyclonal antibody. Survivin displayed two kinds of immunoreactivity: (i) a diffuse cytoplasmic staining and (ii) a distinct nuclear staining. A score-scale to distinguish positive (score 1-2) vs. negative (score 0) pattern was applied. Clinical and biological (nuclear and cytoplasmic survivin staining) covariables were screened for a prognostic relationship with overall survival (OS) and disease-free survival (DFS) into the univariate and multivariate analyses. RESULTS: Data referring to 116 NSCLC patients who underwent surgery for stage I-IIIA NSCLC were collected. Multivariate analyses identified tumor size, nodal status and nuclear, but not cytoplasmic, expression of survivin as significant independent predictors of OS, with a hazard ratio of 2.40 (95% CI 1.44, 3.99, p=0.001), 2.03 (95% CI 1.26, 3.26, p=0.003) and 1.83 (95% CI 1.01, 3.30, p=0.044), respectively. Median OS for nuclear survivin positive (score 1-2) and negative (score 0) patients were 23 months (95% CI 15, 31) and 36 months (95% CI 1, 76), respectively (p=0.01); five-year survival for score 1-2 and score 0 patients were 20% and 44.5%, respectively. Conversely, no significant impact on survival is found when patients are stratified according to cytoplasmic survivin expression. CONCLUSIONS: Data presented herein open the issue that prognosis of stage I-IIIA NSCLC can be linked to the cellular pattern of distribution of survivin.
Assuntos
Biomarcadores Tumorais/metabolismo , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Núcleo Celular/metabolismo , Citoplasma/metabolismo , Neoplasias Pulmonares/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Proteínas de Neoplasias/metabolismo , Adulto , Idoso , Carcinoma Pulmonar de Células não Pequenas/cirurgia , Feminino , Humanos , Proteínas Inibidoras de Apoptose , Neoplasias Pulmonares/cirurgia , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Estudos Retrospectivos , SurvivinaRESUMO
The HPV genotype concordance in the sexual couples could support the sexual viral transmission of HPV infection. The present study contains a case-report of a stable Italian sex couple harbouring the same five HPV genotypes in their genital samples. The female partner, affected by vulvar condilomatosis, evidenced positivity in her cervicovaginal scraping with high risk HPV DNA Hybrid Capture 2 test and was negative at liquid-based performed Pap Test and at colposcopic examination. The male partner was clinically healthy regarding his external genitalia. In both male and female genital scrapings, the following HPV genotypes were detected by means of a PCR-based assay: 6, 16, 53, 73 and 84. This considerably high genotype concordance does not appear to be casual and supports, in our opinion, the hypothesis that genital HPV types are sexually transmitted agents
Assuntos
Papillomaviridae/genética , Infecções por Papillomavirus/transmissão , Infecções por Papillomavirus/virologia , Parceiros Sexuais , Feminino , Genótipo , Humanos , Masculino , Papillomaviridae/isolamento & purificaçãoRESUMO
Morphologic examinations of salivary gland neoplasias arising in male BALB/c (H-2d) mice carrying the activated HER-2/neu (BALB-NeuT) indicate that expression of the oncogene product in the ductal-acinar structures results in a very human-like acinic cell adenocarcinoma with a smoldering course and infrequent metastatization. Typical and then atypical hyperplasia of ducts and acini preceded the rise of salivary tumors that originated from the confluence of multiple ductal hyperplastic foci, while hyperplastic acini behaved as an abortive preneoplastic lesion. The vascular network in normal, hyperplastic and neoplastic salivary tissue was analysed to see whether activation of the angiogenic process is essential in salivary gland carcinogenesis. Immunostaining with anti-endothelial cells (anti-CD31), anti-beta3 integrin and anti-laminin antibodies revealed that microvessel density was significantly higher in normal and hyperplastic than in neoplastic tissue, in which no signs of new vessel sprouting were found. Assessment of angiogenic factor expression indicates a low presence of VEGF in normal, hyperplastic and neoplastic epithelium, while bFGF was preferentially produced but not exported by neoplastic cells and remained in a cell-associated form. Our data suggest that normal salivary gland vascularization is able to support tumor onset and development with no need for an angiogenic switch.
Assuntos
Neovascularização Patológica/patologia , Receptor ErbB-2/fisiologia , Neoplasias das Glândulas Salivares/irrigação sanguínea , Animais , Apoptose , Fatores de Crescimento Endotelial/análise , Feminino , Hiperplasia , Imuno-Histoquímica , Linfocinas/análise , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Transgênicos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Neoplasias das Glândulas Salivares/etiologia , Neoplasias das Glândulas Salivares/patologia , Glândulas Salivares/patologia , Glândulas Salivares/ultraestrutura , Fator A de Crescimento do Endotélio Vascular , Fatores de Crescimento do Endotélio VascularRESUMO
Morphologic examinations of mammary neoplasias arising in BALB/c (H-2d) mice carrying the activated rat HER-2/neu oncogene (BALB-NeuT), and in FVB (H-2q) mice bearing the wild-type proto-oncogene (FVB-NeuN), indicate that both conditions result in a very human-like lobular carcinoma of alveolar type, whose histotype is the result of the preferential expression of HER-2/neu products in the epithelium of lobular ducts and lobules. Detailed analysis of tumor progression indicates that transition from lobular hyperplasia to overt carcinoma is associated with a high epithelial proliferation rate, as assessed by anti-proliferating cell nuclear antigen immunostaining, and coincides with the activation and maximal extension of tumor angiogenic process as assessed by microvessel count (anti-CD31), anti-beta3 integrin, and anti-laminin immunostaining. Neovascularization is accompanied by vascular endothelial cell growth factor and basic fibroblast growth factor production by hyperplastic epithelial cells. By contrast with the BALB-NeuT tumors, E-cadherin expression is almost nonexistent in those arising in FVB-NeuN mice and this may explain their high metastatic potential. Despite their different kinetics, however, the lung metastases observed in both strains are histologically similar and resemble the primary tumor. Both strains can thus be proposed as models for "in vivo" investigation of the origin and progression of the alveolar type of lobular mammary carcinoma and the testing of new therapeutic approaches.
Assuntos
Carcinoma Lobular/patologia , Genes erbB-2 , Neoplasias Mamárias Experimentais/patologia , Animais , Carcinoma Lobular/genética , Progressão da Doença , Feminino , Masculino , Neoplasias Mamárias Experimentais/genética , Camundongos , Camundongos Transgênicos , Proto-Oncogene Mas , Ratos , Receptores de Estrogênio/análise , Receptores de Progesterona/análise , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
OBJECTIVE: To investigate the effectiveness of immunohistochemical technique to detect Helicobacter pylori (H. pylori) in patients treated with triple therapy. METHODS: Forty patients (18 men, 22 women, mean age 43 years) with active antral gastritis, H. pylori positive at urease test, culture, and histology, were treated for 1 wk with omeprazole, amoxicillin, and metronidazole. Gastritis was scored according to Sydney criteria. Two months after the end of therapy, endoscopy, urease test, culture, and histology were repeated. RESULTS: Culture and histology were negative in 32 (80%) of treated cases. Biopsy specimens of the eradicated group were stained with immunohistochemical technique using an anti-H. pylori specific polyclonal antibody. In 12 of 32 (37.5%) patients, clusters of round or vibrio-shaped bacteria, unidentified at histology, were stained by the specific anti-H. pylori antibody. After triple therapy, at histology all patients were found with improved gastritis. In six patients however, mucosal-associated lymphoid tissue (MALT) appearance, present before therapy, persisted after therapy. In five of six patients with MALT, immunostaining with anti-H. pylori antibody was positive. CONCLUSIONS: The immunohistochemical technique is more accurate than classical methods in identifying H. pylori after specific therapy. This method should, therefore, be used in all studies that aim to achieve eradication. Whether the H. pylori identified at immunohistochemistry is able to reactivate and induce recrudescence of infection remains to be clarified.
Assuntos
Anticorpos Antibacterianos/análise , Gastrite/microbiologia , Infecções por Helicobacter/diagnóstico , Helicobacter pylori/imunologia , Adulto , Idoso , Amoxicilina/administração & dosagem , Antibacterianos/administração & dosagem , Antiulcerosos/administração & dosagem , Biópsia , Quimioterapia Combinada , Feminino , Gastrite/tratamento farmacológico , Gastrite/patologia , Infecções por Helicobacter/tratamento farmacológico , Infecções por Helicobacter/patologia , Humanos , Imuno-Histoquímica , Masculino , Metronidazol/administração & dosagem , Pessoa de Meia-Idade , Omeprazol/administração & dosagem , Penicilinas/administração & dosagem , Antro Pilórico/microbiologia , Antro Pilórico/patologiaRESUMO
Injection of interleukin-4 (IL4) gene-transduced tumour cells into syngeneic immunocompetent mice resulted in tumour rejection in which a key role for eosinophils was suggested. To evaluate whether IL5 inhibits tumour growth by selectively inducing eosinophil recruitment and activation, a poorly differentiated mammary adenocarcinoma cell line (TSA) was transfected with the IL5 gene and the cells secreting IL5 (TSA-IL5) were injected subcutaneously (s.c.) in syngeneic mice. The oncogenicity of TSA-IL5 was compared with that exhibited by TSA cells transfected with the IL4 gene (TSA-IL4) and with the neomycin resistance gene only (TSA-neo). At progressive times after subcutaneous challenge, tumour growth areas were studied histologically, ultrastructurally, and immunohistochemically to identify the reactive cells, visualize tumour vessels, and detect the cytokines and chemokines involved in the anti-tumour reaction. Both the morphological and the functional data showed that TSA-IL5, despite the large eosinophil infiltrate, grew progressively like TSA-neo, suggesting that eosinophils per se do not play a crucial role in TSA tumour rejection. Furthermore, our data indicate that the rejection of TSA-IL4 depends on the IL4-induced expression of VCAM-1 and MCP-1 by endothelial cells. MCP-1 together with VCAM-1 results in recruitment and activation of basophils, mast cells, and macrophages, and hence a pro-inflammatory cytokine cascade that initially favours the influx and activation of neutrophils and finally tumour rejection. In this context, the rejection of TSA-IL4 seems to involve a variety of reactive cells and rests on a continuous cross-talk between basophils, mast cells, macrophages, CD8-positive lymphocytes, and granulocyte subsets, mostly neutrophils.
Assuntos
Terapia Genética/métodos , Interleucina-4/genética , Interleucina-5/genética , Neoplasias Mamárias Experimentais/terapia , Animais , Moléculas de Adesão Celular/metabolismo , Endotélio/patologia , Feminino , Neoplasias Mamárias Experimentais/metabolismo , Neoplasias Mamárias Experimentais/ultraestrutura , Camundongos , Camundongos Endogâmicos BALB C , Transplante de NeoplasiasRESUMO
A role in tumor progression has been proposed for transforming growth factor-beta 1 (TGF beta 1) and interleukin (IL)-8 as well as for IL-1, which itself induces the production of TGF beta 1 and IL-8 in many cell types. TGF beta 1 and IL-8 production and their regulation by IL-1 in five non-small-cell (NSC) lung tumor cell lines were evaluated. Moreover, their levels were evaluated in 29 NSC lung tumors. All cell lines constitutively produced TGF beta 1, and three produced IL-8. After IL-1 beta treatment, TGF beta 1 production was upregulated in two cell lines, whereas IL-8 production was markedly upregulated in two, induced in one, and unmodified in two. In tumors, the levels of TGF beta 1, IL-8, and IL-1 beta were higher than in normal counterparts (p < 0.001), and a positive correlation between IL-8 and IL-1 beta levels (p < 0.001) was found. TGF beta 1, IL-8, and IL-1 beta mRNA expression was examined in 12 tumors. TGF beta 1 mRNA was detected in all cases, IL-8 mRNA in 7, and IL-1 beta MRNA was undetectable. TGF beta 1, IL-8, and IL-1 beta immunoreactivity was then studied by immunohistochemistry. TGF beta 1 and IL-8 immunoreactivity was observed in neoplastic cells; IL-1 beta immunoreactivity was observed in mononuclear cells. In conclusion, in tumors IL-1 beta levels positively correlated with those of IL-8, and IL-1 beta as well as TGF beta 1 and IL-8 levels were significantly higher than in normal tissues.
Assuntos
Adenocarcinoma/patologia , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma de Células Escamosas/patologia , Interleucina-1/análise , Interleucina-8/análise , Neoplasias Pulmonares/patologia , RNA Mensageiro/análise , RNA Neoplásico/análise , Fator de Crescimento Transformador beta/análise , Adenocarcinoma/imunologia , Carcinoma Pulmonar de Células não Pequenas/imunologia , Carcinoma de Células Escamosas/imunologia , Humanos , Imuno-Histoquímica , Interleucina-1/imunologia , Neoplasias Pulmonares/imunologia , Células Tumorais CultivadasRESUMO
Interleukin 1alpha (IL-1alpha), Interleukin 6 (IL-6) and epidermal growth factor (EGF) were tested for their ability to regulate epithelial cervical cell cytokine production and secretion and to induce proliferation of human normal and neoplastic epithelial cervical cells. IL-1alpha, and IL-6 enhanced tumour and normal cell growth by 20-120%. The interleukins efficacy was similar to that of EGF for some cell lines but not for normal esocervical cells. The stimulatory effects of the interleukins were observed in both human papilloma virus (HPV)-infected and HPV-non-infected cervical cells. Normal cells constitutively expressed IL-1alpha, IL-6 and EGF mRNA. All cell lines except C33A expressed IL-1alpha mRNA. CaSki, C-4II and HT-3 expressed mRNA for IL-6. IL-1alpha induced or increased IL-6 mRNA levels in the Me-180 and HT-3 lines and in normal cervical cells. IL-6 induced: (1) the expression of its own mRNA only in Me-180 cells that constitutively lacked IL-6 mRNA; (2) the expression of IL-1alpha mRNA in C-33A and increased IL-1alpha mRNA level in the case of Me180 cells. Increased amounts of IL-6 mRNA were found in normal cells when treated with IL-1alpha. In spite of the pattern of mRNA expression, only HT-3 and normal cervical cells constitutively secreted IL-6, and only normal cells were able to produce IL-1alpha protein. A significant IL-1alpha-dependent increase of IL-6 secretion was found in Me-1 80, HT-3 and normal cells. IL-1alpha- and IL-6-driven cell proliferations were almost completely inhibited by the addition of neutralizing anti-IL-6 antibodies. Taken together, these data suggest that interleukins play a role in cervical carcinogenesis as autocrine and/or paracrine stimuli.
Assuntos
Colo do Útero/efeitos dos fármacos , Fator de Crescimento Epidérmico/farmacologia , Interleucina-1/farmacologia , Interleucina-6/farmacologia , Neoplasias do Colo do Útero/patologia , Divisão Celular/efeitos dos fármacos , Colo do Útero/citologia , Colo do Útero/metabolismo , Feminino , Humanos , Interleucina-1/genética , Interleucina-1/metabolismo , Interleucina-1/fisiologia , Interleucina-6/genética , Interleucina-6/metabolismo , Interleucina-6/fisiologia , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Proteínas de Neoplasias/fisiologia , RNA Mensageiro/metabolismo , Células Tumorais Cultivadas/efeitos dos fármacos , Neoplasias do Colo do Útero/metabolismoRESUMO
Warthin's tumor is the second most common salivary gland tumor preceded only by pleomorphic adenoma. In most cases it involves the parotid gland and can, at times, be bilateral. It can also arise in ectopic salivary tissue in the latero-cervical and para-parotid lymph nodes. This neoplasm consists of two histologic components: one epithelial, the other lymphoid. Malignant transformation involving each of these tissues has been reported. However, few cases give clear-cut examples of the epithelial malignant change. Therefore, primary malignant transformation of Warthin's tumor is extremely rare. This event appears related to the initial time of tumor onset and/or past radiotherapy for other malignant cervico-facial lesions. The authors report a case of epidermoid carcinoma arising on an ectopic Warthin's tumor in a 57-year-old male. Physical examination revealed a recent, smooth tumor mass on the left, located near the laryngeal thyroid cartilage. Fine needle aspiration cytology was suspicious of a malignant epithelial neoplasm. Functional latero-cervical dissection, modified by excision of the digastric and sternohyoid muscles plus a 2 x 2 cm section of the overlying skin, was performed in this case. Histology and immunocytochemical tests on the surgical specimen revealed a 14 cytokeratin-positive, malignant epidermoid neoplasm arising from the adjacent 14 cytokeratin-negative, oncocytic epithelium. This relationship may rule out metastasis and may, therefore, be a case of Warthin's tumor associated with an epidermoid carcinoma or a case of branchial cyst.
Assuntos
Adenolinfoma/patologia , Carcinoma de Células Escamosas/patologia , Neoplasias Laríngeas/patologia , Neoplasias Primárias Múltiplas/patologia , Cartilagem Tireóidea/patologia , Adenolinfoma/cirurgia , Adulto , Idoso , Carcinoma de Células Escamosas/cirurgia , Feminino , Humanos , Neoplasias Laríngeas/cirurgia , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Neoplasias Primárias Múltiplas/cirurgia , Cartilagem Tireóidea/cirurgia , Tomografia Computadorizada por Raios XRESUMO
The expression of very late activation antigens (VLAs)-1/6 was correlated with that of the VLA ligands fibronectin, laminin, collagen, and vascular cell adhesion molecule-1 in sections of normal thymus, in thymocyte suspensions, and in 10 cases of thymoma. Capsular epithelial cells are VLA-2+, VLA-3+, and VLA-6+ and face the thymic basement membrane, which is rich in fibronectin, laminin, and collagen type IV. Cortical epithelial cells are VLA-2+ and are embedded in a reticular meshwork of nonorganized extracellular matrix (ECM) that is rich in fibronectin. Cortical thymocytes, identified as CD3dim cells by using immunofluorescence in suspension, are highly positive for VLA-4, a fibronectin ligand. Most cortical macrophages are positive for vascular cell adhesion molecule-1, a molecule recognized by VLA-4. Medullary epithelial cells are VLA-2+/VLA-3+ and are codistributed with fibrous strands of organized ECM that are positive for fibronectin, collagen, and laminin. Medullary thymocytes, identified as CD3bright cells, are positive for VLA-4 and VLA-6, a ligand for laminin. Our findings suggest that intrathymic thymocyte maturation is associated with changes in expression of VLA molecules, which are apparently correlated with the presence of VLA ligands in the tissue microenvironment. Thymomas were classified as cortical (three), common (five), or medullary (two) type. Expression of VLA molecules and distribution of ECM in the three histological subtypes were reminiscent of those observed in the respective regions of the normal thymus. All cases of thymoma were characterized by overexpression of VLA molecules on neoplastic cells, which was associated with increased deposition of organized ECM rich in fibronectin, laminin, and collagen.