Abstract

Allelic deletions of tumor suppressor genes have been observed frequently in a variety of human tumors. These losses are believed to contribute to the development of human cancers. In order to detect loss of heterozygosity(LOH) within one of the well-known tumor suppressor gene, Rb(retinoblastoma), in primary uterine cervical cancers, we analysed four polymorphic intronic sites of Rb locus using polymerase chain reaction(PCR) in 55 primary cervical cancer tissues. The estimated heterozygote frequencies of intronl/BamHI, intronl7/XbaI, intron25/DraI, and intron 20 variable number of tandem repeat(VNTR) regions were 49%, 49%, 42%, and 80%, respectively. The observed frequencies of tumors with LOH at each locus were 21%(5 /24), 17%(5/29), 20%(5/20) and 44%(7/44) for intronl/BamHI, intronl7/XbaI, intron25/DraI and intron 20 VNTR polymorphic loci, respectively. The overall frequency of cervical cancer with at least one LOH at the Rb locus in this study was 14%(7/49), indicating that LOH at the Rb locus was not necessarily associated with cervical carcinogenesis. All the tumors showing LOH at the Rb locus were histologically moderatelv to poorly differentiated types and most of them(5 of the 7, 71%) were over FIGO stage II. These results suggest that the tumors with LOH at this locus may represent the general genomic instability which will contribute to the tumor progression and LOH of this gene may be used as one of the prognostic factors in cervical cancer in the future.

• Keywords: Cervical cancer, Retinoblastoma gene, Loss of heterozygosity