Homozygous deletions on the short arm of chromosome 3 in human oral squamous cell carcinomas

Recent cytogenetic and allelic deletion analyses have demonstrated that del etions on the short arm of chromosome 3 (3p) are frequently found in variou s cancers, including oral squamous cell carcinomas (OSCCs). This suggests t hat one or more tumor suppressor gene(s) for these malignancies might be lo cated on 3p. In the present study, to further define the region(s) on 3p th at harbor putative tumor suppressor gene(s) for OSCCs, we have investigated the existence of homozygous deletions (HDs) at 33 loci on 3p, in 14 OSCC c ell lines. HDs were detected within the FRA3B region at 3p14.2 in only two cell lines (HSC-4 and TSU). Recently, the human fragile histidine triad (FI IIT) gene was isolated from this region, abnormalities of which have been f ound at high frequencies in several types of human cancers. We also examine d the expression of the FHIT gene, using reverse transcription-polymerase c hain reaction IRT-PCR) and exon-specific PCR, in the two OSCC cell lines wh ich showed HDs at 3p14.2. There was no detectable expression of exon 5, whi ch was the first protein-coding exon of FHIT gene, in HSC-4 cells, indicati ng that this region was homozygously deleted ill this cell line. On the oth er hand, IID in the TSU cells did not affect the coding region of the FHIT gene, and the wild-type transcript was detected by RT-PCR. Therefore, sever al candidate turner suppressor genes, including the FHIT gene, may reside i n those homozygously deleted regions. To our knowledge, this is the first r eport of HDs on 3p in OSCCs. (C) 2001 Elsevier Science Ltd. All rights rese rved.