Abstract
The fragile histidine triad gene (FHIT) is a putative tumor suppressor gene (TSG) that spans the fragile chromosomal site FRA3B at 3p14.2. To elucidate the role of this TSG in tumorigenesis, the transcripts of 81 primary neoplasias of various tumor types and 10 benign tumors (leiomyoma uteri) are being compared to those of constitutive tissue of the same patients. Total RNA is extracted from all samples and reverse-transcribed into cDNA. Exons 3-10 including the translated exons 5–9 are PCR-amplified. The transcripts of each tumor/constitutive panel are first quantified and analyzed for size differences of > 50 bp in agarose gels. In one of 71 panels analyzed (1/71), the tumor FHIT was underexpressed compared to actin while 6/71 yielded size differences within the panel Next, the transcripts are compared by restriction endonuclease fingerprinting (REF); using specific conditions, this modified SSCP technique allows detection of any nucleotide change. Of 45 tumor panels analyzed by REF, 39 contained mutations: 5/5 breast, 9/9 colon, 2/3 endometrial, 4/5 kidney, 1/1 liver, 3/3 lung, 3/3 ovarian, 3/4 skin, 4/4 stomach, 1/1 Wilms' and 4/7 leiomyoma uteri. Samples that revealed mutations are being sequenced. At least one breast cancer had lost the entire exon 4 and 1 Ibp of the 5′ end of exon 10, the same deletion as was reported missing in a lung cancer cell line. Combined results to date suggest that FHIT is nonrandomly mutated in breast as well as colon cancer and, most likely, in many other tumor types. Future work will include an analysis of underexpressed transcripts for transcriptional inactivation by hypermethylation.
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Kaelbling, M. Mutation analysis of the fragile histidine triad gene transcripts of primary tumors and unaffected tissue using restriction nuclease fingerprinting and sequencing. Genet Med 1, 73 (1999). https://doi.org/10.1097/00125817-199901000-00127
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DOI: https://doi.org/10.1097/00125817-199901000-00127