Living unrelated kidney transplantation.
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Biomedical subjects
Publications and source records attributed to A Baldi.
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p53 mutations are among the most frequent genetic alterations reported in human lung cancer. Although the prognostic value of altered p53 expression is still debated, it is accepted widely that estimation of the proliferation rate has an important prognostic role. Moreover, an association between certain types of human lung cancers and tobacco use is well known. Drawing from this background, we investigated the immunohistochemical expression of mutant oncogenic p53 protein, and related it to the smoking history of 61 patients with non-small cell lung carcinoma (NSCLC) and to the expression pattern of proliferating cell nuclear antigen (PCNA), which is considered to be an important negative prognostic factor in several neoplasms. We found p53 overexpression in 22 (36.1%) specimens, including 16 squamous carcinomas (41%) and six (27.2%) adenocarcinomas. PCNA nuclear staining was detected in 98.4% of the specimens, and a significantly higher PCNA expression score was found in all of the p53-positive samples. When the patient survival time was compared, p53 accumulation had a statistically significant negative prognostic value (P < .001). This was supported by a Kaplan-Meier survival percentage plot of immunohistochemically p53-undetectable specimens and p53-detectable specimens. These latter patients had a greatly reduced survival time. A relationship was established between p53 immunohistochemical detection and the smoking history of the patients. None of the specimens from the nonsmoking patients expressed immunohistochemically detectable p53 protein. Altered p53 expression was detected in 40.7% of smoking patients. Our findings support the hypothesis of involvement of p53 mutations in tobacco-induced carcinogensis and indicate that altered p53 expression plays an important prognostic role in NSCLC in smokers.
The prognosis of differentiated carcinoma of the thyroid has been reported to be extremely favourable. Previous studies have concluded that lymph node metastasis do not affect survival rates in patients with differentiated thyroid carcinoma. Therefore, nodal metastasis has not been evaluated as a prognostic factor in recent definitions of risk groups. To determine the significance of nodal disease, we reviewed 219 consecutive patients with differentiated thyroid cancer (191 papillary, 14 follicular and 14 Hurtle cell carcinomas). Fifty-five patients were treated with modified neck dissection and all of them received adjuvant radioiodine. There were recurrences in 25 patients (11.4%), with follow-up ranging from 6 months to 14 years. Systemic disease occurred synchronously in two patients, and four patients died of thyroid carcinoma.
The oncoprotein of simian virus-40, SV40 large T-antigen (Tag), is reported to target and to inactivate growth suppressive proteins such as the retinoblastoma family and p53 (ref. 4, 5), leading to transformation of human cell lines in vitro, tumor production in rodents, and detection of Tag in several human cancers including mesotheliomas. The retinoblastoma family contains three members, pRb, p107 and pRb2/p130 (ref. 9), that are phosphorylated in a cell cycle-dependent manner, have cell growth suppressive properties and bind to specific members of the E2F family and various cyclins. Even though mesotheliomas are among the most aggressive human cancers, alterations of important cell-cycle "controllers," such as the Rb family genes, have never been reported in these tumors. We found the presence of SV40-like sequences in 86% of 35 archival specimens of mesothelioma. We also demonstrated that SV40 Tag, isolated from frozen biopsies of human mesothelioma, binds each of the retinoblastoma family proteins, pRb, p107 and pRb2/p130, in four of four specimens. We propose that the tumorigenic potential of SV40 Tag in some human mesotheliomas may arise from its ability to interact with and thereby inactivate several tumor and/or growth suppressive proteins.
Mab B21 is a monoclonal antibody (Mab) that recognizes an epithelial tumor surface antigen (ETSA-B21) from diverse human tumor cell lines including breast, ovary, uterus, and their cognate carcinoma tissues. A lower reactivity has been observed in normal breast tissue and benign hyperplesia. In this study, the characteristics of the ETSA-B21 antigen have been examined in greater detail in the MCF-7, SK-BR-3, and MDA-MB-453 breast cancer cell lines. Treatment with phosphatidylinositol-phospholipase C, but no neuraminidase were found to partially remove the ETSA-B21 signal from the cell surface as revealed by immunofluorescence microscopy. Inhibition of the N-glycosylation pathway by tunicamycin resulted in a decreased ETSA-B21 signal on the cell membrane. In addition, the antigen-antibody complex was internalized in breast cancer cells as demonstrated by an acidic was internalization assay evaluated using immunofluorescence. In conclusion, this study suggests that ETSA-B21 is a GPI anchor N-glycosylated protein promoting specific antibody internalization in breast cancer cells.
We examined the effects of histamine and its agonists on the expression of the c-fos and c-myc proto-oncogenes at the transcriptional and translational levels in the human promonocytic U937 cell line. Histamine transiently increased cAMP and c-fos expression through H2 receptors. Dibutyryl cAMP also increased c-fos mRNA and protein, and levels remained elevated even after 12 hr of treatment. Dose-dependence studies using histamine and dimaprit showed that the EC50 values for cAMP production and c-fos increase were similar, suggesting that cAMP might be involved in c-fos induction via H2 receptors. Furthermore, studies carried out using H7, a protein kinase A/protein kinase C inhibitor, blocked c-fos induction, whereas no effect was observed with bisindolylmaleimide, a specific protein kinase C inhibitor. No modification of c-myc expression could be detected on treatment with histamine or its analogues. Nevertheless, dibutyryl cAMP induced a down-regulation of the levels of this proto-oncogene. In addition, dibutyryl cAMP inhibited cell growth in a dose-dependent manner, whereas histamine failed to affect proliferation and differentiation of U937 cells. Cells pretreated with dimaprit showed a decrease in the cAMP response to subsequent addition of H2 agonists, whereas the cAMP response to prostaglandin E2 remained unaltered. This homologous mechanism of H2 receptor desensitization was time dependent. These results indicate that histamine activates several mechanisms involved in the induction of differentiation, such as cAMP and c-fos production, but fails to promote differentiation of U937 cells, apparently due to the rapid desensitization of H2 receptors.
Congenital cystic adenomatoid malformation of the lung (CCAM) is characterized by an adenomatoid proliferation of bronchiole-like structures and cysts formation. The condition is most commonly found in newborns and children and it may be associated with other malformations; rarely, the presentation is delayed until adulthood. This paper presents a case of CCAM in a 62-year-old male, who presented with recurrent bacterial pneumonias and breathlessness one exertion. The chest X-rays and CT scan revealed a patchy opacity in the right lower pulmonary zone. Bronchoscopic examination was normal. At surgery, a mass involving the right lower and middle lobes, and enlargement of hilar lymph nodes were found. A bilobectomy was performed without complications. Examination of the gross specimen showed a lesion characterised by multiple small cysts, all less than 1 cm in diameter; they were lined predominately by columnar epithelium, occasionally by ciliated epithelium. Rare cysts were lined by foreign body giant cells. Elastic fibers and smooth muscle were present within the cysts wall. Peripherally, there were normal alveoli and bronchioli mixed with cysts, and plasmalymphocytic infiltrates. The final diagnosis was Stocker's Type II CCAM of the lung. CCAM of the lung is a rare development lesion of the lung and it has no sexual predilection. It is usually unilateral and sublobar or lobar in size, but occasionally it can be multilobar. Typical histologic feature of CCAM are adenomatoid proliferation of bronchiole-like structures and macro- or microcysts lined by columnar or cuboidal epithelium and absence of cartilage and bronchial glands. Inflammatory changes are not found in infants, but may be present in adult patients. Based on the size of the cysts, CCAM may be classified into three different types: type I characterised by multiple cysts, over than 1 cm in diameter; type II with smaller cysts, less than 1 cm in diameter; type III that shows solid lesions composed of bronchiole-like structures. Type II is commonly found in childhood, but is occasionally seen in adult patients, as that one in our report. The insult probably occurs between 4th and 7th week of fetal life. The etiologic agent is unknown. The histologic diagnosis of CCAM is difficult in adult patient, perhaps because of supervening infections that sometimes distort the underlying diagnostic pathologic appearances and make them difficult to recognise, as happened in our case. From the clinical point of view, most of the lesions cause severe respiratory failure; in adult individuals the diagnosis is difficult, since there are very few relevant symptoms and signs. The patients can present with fever, recurrent infections, breathlessness and haemoptysis. The chest X-rays abnormalities are not specific and include homogeneous or multicystic opacities. Similarly, other diagnostic methods add no further useful informations. Surgical treatment is necessary also in adult patients, because of the risk of recurrent pulmonary infections and malignancies associated with CCAM. Lobectomy is the treatment of choice, but sometimes a larger resection is required, when the lesion involves more than one lobe.
Pulmonary blastoma is a rare tumor of the lung consisting of immature mesenchyma and epithelial structures that can mimic the structure of the embryonic lung. In this article, we report a case of pulmonary blastoma occurred in an adult individual. We review the literature concerning this rare neoplasm that includes less than one hundred cases reported. We also describe the pathologic features of this disease which is microscopically divided in two classes: 1) lesions composed solely of malignant gland of embryonic appearance (WDFA: Well-Differentiated Fetal Adenocarcinomas), and 2) lesions with biphasic appearance, containing both neoplastic glands and either adult sarcomatous or embryonic mesenchyme. The adult pulmonary blastomas are considered as an entity distinct from childhood blastomas. This condition may be frequently asymptomatic; if symptomatic, it show the same clinical picture of a mass in the lung impinging on bronchi or pleura; the most usual symptoms include cough, hemoptysis, and chest pain. Chest radiography typically shows a peripheral or central lung opacity without preference for any lobe. The prognosis is poor, due to the high incidence of metastasis. Histologic class and clinical findings can be of prognostic value in pulmonary blastoma. We believe that an early diagnosis is essential: in our case, this allowed a complete resection of the tumor and the patient is still alive without recurrence 3 years after the surgical treatment.
Two proteins, p107 and pRb2/p130, which are structurally and functionally similar to the product of the retinoblastoma gene (pRb), were cloned by taking advantage of their ability to bind transforming proteins of DNA tumor viruses through a particular region called the "pocket domain." Like pRb, both proteins play a fundamental role in growth control. Using immunocytochemical techniques, we examined a variety of normal human tissues for the expression of pRb2/p130 and p107. Both proteins were expressed ubiquitously, although a different tissue distribution and/or level of expression were found in various organs. Terminally differentiated cells, such as neurons and skeletal muscle, showed high expression levels for Rb2/p130, whereas p107 was expressed at higher levels in other cell types such as epithelia of the breast and prostate. We then examined the expression pattern of Rb2/p130 in 158 specimens of human lung cancer and found an inverse correlation between the histological grading of the tumors, the development of metastasis, and the level of expression of Rb2/p130.
Two genes, p107 and Rb2/p130, are strictly related to RB, the most investigated tumor suppressor gene, responsible for susceptibility to retinoblastoma. The products of these three genes, namely pRb, p107, and pRb2/p130 are characterized by a peculiar steric conformation, called "pocket," responsible for most of the functional interactions characterizing the activity of these proteins in the homeostasis of the cell cycle. The interest in these genes and proteins springs from their ability to regulate cell cycle processes negatively, being able, for example, to dramatically slow down neoplastic growth. So far, among these genes, only RB is firmly established to act as a tumor suppressor, because its lack-of-function is clearly involved in tumor onset and progression. It has been found deleted or mutated in most retinoblastomas and sarcomas, but its inactivation is likely to play a crucial role in other types of human cancers. The two other members of the family have been discovered more recently and are currently under extensive investigation. We review analogies and differences among the pocket protein family members, in an attempt to understand their functions in normal and cancer cells.
The secreted proteoglycan decorin has been implicated in the negative control of cell proliferation primarily by virtue of its ability to block transforming growth factor-beta. Moreover, decorin expression is markedly up-regulated during quiescence but suppressed upon viral transformation, whereas de novo decorin expression in colon carcinoma cells abrogates the malignant phenotype by arresting the cells in the G1 phase of the cell cycle. Here we show that this decorin-induced growth arrest is associated with up-regulation of p21 mRNA and protein in a transforming growth factor-beta- and p53-independent pathway. The augmented p21 protein is present as a multimeric complex with various cyclins and cyclin-dependent kinases in the nuclei of decorin-expressing cells, thereby leading to suppression of cyclin-dependent kinase activity and block of cell division. Through the usage of decorin-specific antisense oligodeoxynucleotide treatment, we demonstrate that the expression of decorin is closely linked to that of p21 and that abrogation of decorin leads to suppression of p21 and restoration of cell division. Collectively, our results provide a plausible mechanism by which decorin may contribute to retard and suppress the growth of tumor cells in vivo.
The human Rb2/p130 gene shares many structural and functional features with the retinoblastoma gene and the retinoblastoma-related p107 gene. In the present study, we have cloned and partially sequenced the gene coding for the Rb2/p130 protein from human genomic libraries. The complete intron-exon organization of this gene has been elucidated. The gene contains 22 exons spanning over 50 kb of genomic DNA. The length of individual exons ranges from 65 to 1517 bp. The largest intron spans over 9 kb, and the smallest has only 82 bp. The 5' flanking region revealed a structural organization characteristic of promoters of "housekeeping" and growth control-related genes. A typical TATA or CAAT box is not present, but there are several GC boxes and potential binding sites for numerous transcription factors. This study provides the molecular basis for understanding the transcriptional control of the Rb2/p130 gene and for implementing a comprehensive Rb2/p130 mutation screen using genomic DNA as a template.
The retinoblastoma (Rb) family consists of the tumor suppressor pRb and related proteins p107 and pRb2/p130. Ectopic expression of pRb and p107 results in a growth arrest of sensitive cells in the G1 phase of the cell cycle. We demonstrated here that the growth-suppressive properties of pRb2/p130 were also specific for the G1 phase. The A-, E-, and D-type cyclins as well as transcription factor E2F1 and the E1A viral oncoprotein were able to rescue the pRb2/p130-mediated G1 growth arrest in SAOS-2 cells. The rescue with cyclins A and E correlated with their physical interaction with pRb2/p130, which surprisingly has been found to occur over all phases of the cell cycle. The phosphorylation status as well as the kinase activity associated with pRb2/p130 dramatically increased near the G1-S-phase transition. This suggests that, like the other Rb family members, pRb and p107, the phosphorylation of pRb2/p130 is controlled by the cell cycle machinery and that pRb2/p130 may indeed be another key G1-S-phase regulator.
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The retinoblastoma gene family is composed of three members: the retinoblastoma gene, one of the most well studied tumor suppressor genes and two related proteins, p107 and pRb2/p130. These three proteins share many structural and functional features and play a fundamental role in growth control. Intense investigation of these proteins has identified a series of similar cell-cycle regulators and transcription factors with which they interact. Although the precise function of the retinoblastoma gene product and its relatives remains unknown, recent data suggests that they play parallel roles in controlling cell cycle progression and promoting cellular differentiation. In this review, we will attempt to clarify some of the molecular mechanisms by which these three related proteins cooperate to control cellular proliferation and differentiation.
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The Rb (retinoblastoma) gene family is composed of three members: the RB gene (one of the best-studied tumor suppressor genes) and two related genes, p107 and pRb2/p130. These three proteins share many structural and functional features and play a fundamental role in growth control. Using immunocytochemical techniques, we evaluated a variety of lung tumor specimens for the expression of this family of proteins and compared protein expression with the histological grading of the tumors and with the expression of the proliferating cell nuclear antigen. These Rb family members displayed distinctive patterns when compared and contrasted using different parameters. The highest percentage of undetectable levels in all of the specimens examined and the tightest inverse correlation (P) with the histological grading and with proliferating cell nuclear antigen expression in the most aggressive tumor types were found for pRb2/p130, which may suggest an important role for this protein in the pathogenesis and progression of lung cancer.
The Rb2/p130 protein has been shown to have a high sequence homology with the retinoblastoma gene product (pRb), one of the most well-characterized tumor suppressor genes, and with pRB-related p107, especially in their conserved pocket domains, which display a primary role in the function of these proteins. In this study, we report on the biochemical and immunocytochemical characterization of the Rb2/p130 protein, using a polyclonal antibody developed against its "spacer" region included in the pocket domain of the whole protein. We show that pRb2/p130 is a phosphoprotein located at the nuclear level and that its phosphorylation pathway can be dramatically reduced by phosphatase treatment. Moreover pRb2/p130 with p107, is one of the major targets of the E1A viral oncoprotein-associated kinase activity, showing a phosphorylation pattern which is modulated during the cell cycle, reaching a peak of activation at the onset of S-phase.