Detection of frameshift mutations of RIZ in gastric cancers with microsatellite instability.
OBJECTIVE
To study the frameshift mutations of the retinoblastoma protein-interacting zinc finger gene RIZ in gastric cancer with microsatellite instability, and to identify two coding polyadenosine tracts of RIZ.


METHODS
Frameshift mutations at (A)8 and (A)9 tracts of RIZ were detected in 70 human gastric cancer (HGC) specimens by DHPLC and DNA sequencing. Microsatellite instability (MSI) status was assessed by two mononucleotide markers, BAT26 and BAT25, by means of denaturing high-performance liquid chromatography (DHPLC).


RESULTS
In 70 HGC samples, 8 (11.4%) were found positive for instabilities at BAT26 and BAT25. In 7 of the 8 cases with instabilities at both BAT26 and BAT25 (MSI-H), 1 was unstable at BAT26 but stable at BAT25. Frameshift mutations were identified in 4 (57.1%) of the 7 samples with MSI-H in the (A)9 tract of RIZ without mutations in the (A)8 tract. In contrast, frameshift mutations were found in neither of the polyadenosine tracts in 63 samples of MSI-L or MSI stable tumors. Pro704 LOH detection in 4 cases with frameshift mutations did not find LOH in these cases.


CONCLUSIONS
Frameshift mutations of RIZ may play an important role in gastric cancers with MSI.
Pan
Kai-Feng
KF
Department of Cancer Epidemiology, Peking University School of Oncology, Beijing Institute for Cancer Research, Beijing Cancer Hospital, Beijing 100034, China.
Lu
You-Yong
YY
Liu
Wan-Guo
WG
Zhang
Lian
L
You
Wei-Cheng
WC
D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D016368:Frameshift Mutation; D011495:Histone-Lysine N-Methyltransferase; D006801:Humans; D019656:Loss of Heterozygosity; D008297:Male; D018895:Microsatellite Repeats; D009687:Nuclear Proteins / Q000235:genetics*; D013274:Stomach Neoplasms / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*
D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D014157:Transcription Factors; D011495:Histone-Lysine N-Methyltransferase; C093563:PRDM2 protein, human