Role of the retinoblastoma protein in the pathogenesis of human cancer.
ABSTRACT The retinoblastoma gene (RB-1) was originally identified as the gene involved in hereditary retinoblastoma. However, RB-1 mutations are found in a number of common mesenchymal and epithelial malignancies. The retinoblastoma protein (pRB) acts as a transcriptional regulator of genes involved in DNA synthesis and cell-cycle control. In this regard, the functional interaction between pRB and the E2F transcription factor family appears to be critical. The pRB-E2F interaction is, in turn, regulated by a pathway that includes cyclin D1, cdk4, and p16. Mutations that affect this pathway have been documented in nearly every type of adult cancer. Thus, perturbation of pRB function may be required for the development of cancer. Insights into the biochemical functions of pRB, and its upstream regulators, may form the basis for the development of novel antineoplastic agents.
SourceAvailable from: Renato Borges Fagundes[Show abstract] [Hide abstract]
ABSTRACT: Squamous cell carcinoma of the esophagus is a lethal cancer and carries a poor prognosis because of late diagnosis. Identification of molecular markers may aid early diagnosis. We assessed the expression of CDKN2A/RB1 in the esophageal mucosa and its association with the histology. Esophageal biopsies were collected from 38 patients with no esophageal lesion (group 1), from iodine-negative areas of 108 alcoholics/smokers (group 2), and from tumor and nontumor areas in 41 patients with squamous cell carcinoma (group 3). The histologic diagnosis was compared with immunoexpression of CDKN2A/RB1. In group 1, histology showed normal mucosa/mild esophagitis and no expression of CDKN2A/RB1. In groups 2 and 3, the diagnosis was: normal mucosa (38.4%), esophagitis (44.4%), dysplasia and carcinoma in situ (2.8%), and carcinoma (14.3%). The immunoexpression of CDKN2A/RB1 increased in a stepwise manner from the normal mucosa, to esophagitis, dysplasia/carcinoma in situ, and carcinoma (P<0.01). CDKN2A/RB1 was not expressed in the esophageal mucosa of patients without risk factors. p16/pRb expression increased in a stepwise manner, according to the severity of histologic lesions, in biopsies from patients exposed to risk factors or with carcinoma. Esophageal mucosa exposed to risk factors with the expression of those proteins may be at risk for malignant transformation.Applied immunohistochemistry & molecular morphology: AIMM / official publication of the Society for Applied Immunohistochemistry 07/2014; 22(9). DOI:10.1097/PAI.0000000000000011 · 2.06 Impact Factor
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ABSTRACT: The infection with high-risk human papillomavirus (HR-HPV) is the most important risk factor for development of cervical cancer. The intra-type variations of HPV have different biological and pathological consequences with respect to disease progression. In the present study, six major Indian variants were experimentally identified in E6 gene of HPV-16 and showed their impact on immunogenicity by in silico methods. Four different phylogenetic lineages were observed in sequences including European (E) prototype, European variant, Asian and American Asian variant classes and complete absence of African phylogenetic lineages. On the prediction of B- and T- cell epitopes, 18 & 23 potent epitopes for MHC-II alleles, 10 potent MHC-I and 15 B-cell epitopes in each reference and variant sequence were identified. Interestingly, the presence of variation H78Y and L83V result in creation of four new epitope for the HLA-DQA1*0101/DQB1*0501. Out of 15 B-cell predicted epitopes, three most potent epitopes were identified in both reference and variant sequence. Notably the amino acid stretch from amino acid 16 to 60 and 76 to 94 are very important for the immunological properties of E6 protein because these regions contain majority of the predicted epitopes. In future, this could control the cervical cancer by targeting these amino acid stretches for the development of HPV-16 vaccine. Copyright © 2015. Published by Elsevier B.V.Journal of virological methods 03/2015; 218. DOI:10.1016/j.jviromet.2015.03.008 · 1.88 Impact Factor
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ABSTRACT: Purpose To review the progress made in understanding the genetic basis, molecular pathology, and treatment of retinoblastoma since the previous Jackson lecture on the topic was published 50 years ago. Design Perspective based on personal experience and the literature. Methods The literature regarding retinoblastoma was reviewed since 1963. Advances in understanding the biology and treatment of retinoblastoma provided context through the author’s clinical, pathological and research experiences. Results Retinoblastoma was first identified in the 1500s and defined as a unique clinicopathologic entity in 1809. Until the mid-1900s, knowledge advanced sporadically, with technological developments of ophthalmoscopy and light microscopy, and with the introduction of surgical enucleation, chemotherapy and radiation therapy. During the last 50 years, research and treatment have progressed at an unprecedented rate due to innovations in molecular biology and the development of targeted therapies. During this time period, the retinoblastoma gene was discovered; techniques for genetic testing for retinoblastoma were developed; and plaque brachytherapy, chemoreduction, intraarterial chemotherapy, and intraocular injections of chemotherapeutic agents were successfully introduced. Conclusions Nearly all patients with retinoblastoma in developed countries can now be cured of their primary cancer- a remarkable achievement for a childhood cancer that once was uniformly fatal. Much of this success is owed to deciphering the role of the Rb gene, and the benefits of targeted therapies, such as chemoreduction with consolidation as well as intra-arterial and intravitreal chemotherapies. Going forward, the main challenge will be ensuring that access to care is available for all children, particularly those in developing countries.American Journal of Ophthalmology 11/2014; 158(5). DOI:10.1016/j.ajo.2014.07.025 · 4.02 Impact Factor