title: Lack of TNFalpha mRNA expression in cervical cancer is not associated with loss of heterozygosity at 6p21.3, inactivating mutations or promoter methylation.
abstract: Infection with oncogenic human papillomavirus (HPV) is considered to be the major etiologic event for cervical cancer. Tumor necrosis factor alpha (TNFalpha), a proinflammatory cytokine, may be involved in orchestrating an antitumor immune response against human papillomavirus expressing cervical cancer cells. Hence, loss of TNFalpha could be advantageous for tumor cells to escape immune clearance. The aim of our study was to investigate TNFalpha gene expression and epigenetic characteristics associated with the loss of TNFalpha expression in cervical cancer. To this end, we examined TNFalpha expression, loss of heterozygosity (LOH) at 6p21.3, the locus of TNFalpha, mutational status of the TNFalpha locus, loss of the TNFalpha promoter variant 2 allele and CpG hypermethylation of the TNFalpha promoter. RNA in situ hybridization showed absence of TNFalpha expression in 45% of 63 tumors. LOH occurred in 57% of the tumors and was not concordant with absence of TNFalpha mRNA. No mutations in the TNFalpha gene were identified in 15 cases deficient in TNFalpha expression exhibiting LOH. Furthermore, lack of TNFalpha expression did not correlate with promoter methylation. In conclusion, TNFalpha mRNA expression is absent in nearly half of the cervical tumors analyzed. Neither promoter methylation nor genetic causes for lack of expression were evident.
authors.affiliation: Department of Pathology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, The Netherlands.
authors.forename: Judith N
authors.initials: JN
authors.lastname: Kloth
authors.forename: Arko
authors.initials: A
authors.lastname: Gorter
authors.forename: Natalja
authors.initials: N
authors.lastname: ter Haar
authors.forename: Willem E
authors.initials: WE
authors.lastname: Corver
authors.forename: Ekaterina S
authors.initials: ES
authors.lastname: Jordanova
authors.forename: Gemma G
authors.initials: GG
authors.lastname: Kenter
authors.forename: Gert Jan
authors.initials: GJ
authors.lastname: Fleuren
mesh_terms: D000483:Alleles; D045744:Cell Line, Tumor; D002896:Chromosomes, Human, Pair 6 / Q000235:genetics*; D018899:CpG Islands / Q000235:genetics; D019175:DNA Methylation; D004252:DNA Mutational Analysis; D005091:Exons / Q000235:genetics; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D019656:Loss of Heterozygosity / Q000235:genetics*; D018895:Microsatellite Repeats / Q000235:genetics; D009154:Mutation / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics* / Q000378:metabolism; D002583:Uterine Cervical Neoplasms / Q000235:genetics* / Q000473:pathology
chemical_list: D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha