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Article: Expression of p21/waf1 in oral squamous cell carcinomas - correlation with p53 and mdm2 and cellular proliferation index

TitleExpression of p21/waf1 in oral squamous cell carcinomas - correlation with p53 and mdm2 and cellular proliferation index
Authors
Issue Date1999
PublisherPergamon. The Journal's web site is located at http://www.elsevier.com/locate/oraloncology
Citation
Oral Oncology, 1999, v. 35 n. 1, p. 63-69 How to Cite?
AbstractThe cyclin-dependent kinase inhibitor p21/waf1 is regulated by p53- dependent and p53-independent pathways. In addition, mdm2 is an oncogene which forms an auto-regulatory loop with the normal p53 protein and its role has been implicated in oncogenesis. To determine whether a correlation exists between the expression of these gene products, tumor differentiation, tumor staging and radiation therapy, we investigated the expression of p21, p53 and mdm2, and cellular proliferation by Ki-67 (MIB1) labeling index using immunohistochemistry in 88 human oral squamous cell carcinoma (SCC) samples from 56 patients. Tumor expression of all nuclear proteins was scored according to the percentage of positive cancer nuclei, both with the cancer tissue as a whole as well as in different epithelial compartments of differentiation. Positive p21, p53, mdm2 and MIB1 staining was present in 82.4, 67.8, 25.9 and 98.8% of the SCC samples. The staining in different epithelial compartments of differentiation varied: those of p21 and mdm2 present predominantly in suprabasal and upper regions of the tumors; those of p53 and MIB1 in basal and suprabasal regions. Higher levels of p21 expression were seen in actively proliferating tumors (P = 0.025). p21 expression positively correlated with mdm2 expression but not with p53 expression. Moreover, the level of p21 expression was higher in older patients (P = 0.024) and female patients (P = 0.008). There was no significant association among p53, mdm2 and MIB1. Expression of p53 was higher in tumors with poorer cellular differentiation and in younger patients (P = 0.038 and 0.028). There was no association between tumor stage by TNM classification and the expression of any of these gene products or proliferation index. Radiation therapy did not alter the expression of any of these. To conclude, p21 protein was overexpressed in oral SCCs, and this overexpression was related to cell proliferation index and mdm2 expression but independent of p53 protein alteration. Overexpression of p21 alone appeared to be insufficient to suppress tumor progression.
Persistent Identifierhttp://hdl.handle.net/10722/148153
ISSN
2015 Impact Factor: 4.286
2015 SCImago Journal Rankings: 1.764
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorNg, IOLen_US
dc.contributor.authorLam, KYen_US
dc.contributor.authorNg, Men_US
dc.contributor.authorRegezi, JAen_US
dc.date.accessioned2012-05-29T06:11:08Z-
dc.date.available2012-05-29T06:11:08Z-
dc.date.issued1999en_US
dc.identifier.citationOral Oncology, 1999, v. 35 n. 1, p. 63-69en_US
dc.identifier.issn1368-8375en_US
dc.identifier.urihttp://hdl.handle.net/10722/148153-
dc.description.abstractThe cyclin-dependent kinase inhibitor p21/waf1 is regulated by p53- dependent and p53-independent pathways. In addition, mdm2 is an oncogene which forms an auto-regulatory loop with the normal p53 protein and its role has been implicated in oncogenesis. To determine whether a correlation exists between the expression of these gene products, tumor differentiation, tumor staging and radiation therapy, we investigated the expression of p21, p53 and mdm2, and cellular proliferation by Ki-67 (MIB1) labeling index using immunohistochemistry in 88 human oral squamous cell carcinoma (SCC) samples from 56 patients. Tumor expression of all nuclear proteins was scored according to the percentage of positive cancer nuclei, both with the cancer tissue as a whole as well as in different epithelial compartments of differentiation. Positive p21, p53, mdm2 and MIB1 staining was present in 82.4, 67.8, 25.9 and 98.8% of the SCC samples. The staining in different epithelial compartments of differentiation varied: those of p21 and mdm2 present predominantly in suprabasal and upper regions of the tumors; those of p53 and MIB1 in basal and suprabasal regions. Higher levels of p21 expression were seen in actively proliferating tumors (P = 0.025). p21 expression positively correlated with mdm2 expression but not with p53 expression. Moreover, the level of p21 expression was higher in older patients (P = 0.024) and female patients (P = 0.008). There was no significant association among p53, mdm2 and MIB1. Expression of p53 was higher in tumors with poorer cellular differentiation and in younger patients (P = 0.038 and 0.028). There was no association between tumor stage by TNM classification and the expression of any of these gene products or proliferation index. Radiation therapy did not alter the expression of any of these. To conclude, p21 protein was overexpressed in oral SCCs, and this overexpression was related to cell proliferation index and mdm2 expression but independent of p53 protein alteration. Overexpression of p21 alone appeared to be insufficient to suppress tumor progression.en_US
dc.languageengen_US
dc.publisherPergamon. The Journal's web site is located at http://www.elsevier.com/locate/oraloncologyen_US
dc.relation.ispartofOral Oncologyen_US
dc.subject.meshAdulten_US
dc.subject.meshAge Factorsen_US
dc.subject.meshAgeden_US
dc.subject.meshAged, 80 And Overen_US
dc.subject.meshAntigens, Nuclearen_US
dc.subject.meshCarcinoma, Squamous Cell - Genetics - Metabolism - Pathologyen_US
dc.subject.meshCell Divisionen_US
dc.subject.meshCyclin-Dependent Kinase Inhibitor P21en_US
dc.subject.meshCyclins - Metabolismen_US
dc.subject.meshFemaleen_US
dc.subject.meshHumansen_US
dc.subject.meshImmunohistochemistryen_US
dc.subject.meshMaleen_US
dc.subject.meshMiddle Ageden_US
dc.subject.meshMouth Neoplasms - Genetics - Metabolism - Pathologyen_US
dc.subject.meshNuclear Proteins - Metabolismen_US
dc.subject.meshProto-Oncogene Proteins - Metabolismen_US
dc.subject.meshProto-Oncogene Proteins C-Mdm2en_US
dc.subject.meshSex Factorsen_US
dc.subject.meshTumor Suppressor Protein P53 - Metabolismen_US
dc.titleExpression of p21/waf1 in oral squamous cell carcinomas - correlation with p53 and mdm2 and cellular proliferation indexen_US
dc.typeArticleen_US
dc.identifier.emailNg, IOL: iolng@hkucc.hku.hken_US
dc.identifier.emailLam, KY: akylam@hkucc.hku.hk-
dc.identifier.emailNg, M: hrmeman@HKUCC.hku.hk-
dc.identifier.authorityNg, IOL=rp00335en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1016/S1368-8375(98)00083-9en_US
dc.identifier.pmid10211312en_US
dc.identifier.scopuseid_2-s2.0-0032890039en_US
dc.identifier.hkuros43020-
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0032890039&selection=ref&src=s&origin=recordpageen_US
dc.identifier.volume35en_US
dc.identifier.issue1en_US
dc.identifier.spage63en_US
dc.identifier.epage69en_US
dc.identifier.isiWOS:000077473200010-
dc.publisher.placeUnited Kingdomen_US
dc.customcontrol.immutablesml 130703-

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