Abstract
BackgroundHigh frequency of loss of heterozygosity (LOH) was found at D7S486 in primary gastric cancer (GC). And we found a high frequency of LOH region on 7q31 in primary GC from China, and identified D7S486 to be the most frequent LOH locus. This study was aimed to determine what genes were affected by the LOH and served as tumor suppressor genes (TSGs) in this region. Here, a high-throughput single nucleotide polymorphisms (SNPs) microarray fabricated in-house was used to analyze the LOH status around D7S486 on 7q31 in 75 patients with primary GC. Western blot, immunohistochemistry, and RT-PCR were used to assess the protein and mRNA expression of TESTIN (TES) in 50 and 140 primary GC samples, respectively. MTS assay was used to investigate the effect of TES overexpression on the proliferation of GC cell lines. Mutation and methylation analysis were performed to explore possible mechanisms of TES inactivation in GC.ResultsLOH analysis discovered five candidate genes (ST7, FOXP2, MDFIC, TES and CAV1) whose frequencies of LOH were higher than 30%. However, only TES showed the potential to be a TSG associated with GC. Among 140 pairs of GC samples, decreased TES mRNA level was found in 96 (68.6%) tumor tissues when compared with matched non-tumor tissues (p < 0.001). Also, reduced TES protein level was detected in 36 (72.0%) of all 50 tumor tissues by Western blot (p = 0.001). In addition, immunohistochemical staining result was in agreement with that of RT-PCR and Western blot. Down regulation of TES was shown to be correlated with tumor differentiation (p = 0.035) and prognosis (p = 0.035, log-rank test). Its overexpression inhibited the growth of three GC cell lines. Hypermethylation of TES promoter was a frequent event in primary GC and GC cell lines. However, no specific gene mutation was observed in the coding region of the TES gene.ConclusionsCollectively, all results support the role of TES as a TSG in gastric carcinogenesis and that TES is inactivated primarily by LOH and CpG island methylation.
Highlights
High frequency of loss of heterozygosity (LOH) was found at D7S486 in primary gastric cancer (GC)
Identification of candidate tumor suppressor genes around D7S486 in primary GC In this study, 75 pairs of DNA samples of tumor tissue and matched adjacent non-tumor tissue obtained by microdissection were extracted from patients with primary GC
347 single nucleotide polymorphisms (SNPs) were selected in this region, including 254 SNPs located within genes and 93 SNPs located within expressed sequence tags (EST)
Summary
High frequency of loss of heterozygosity (LOH) was found at D7S486 in primary gastric cancer (GC). We found a high frequency of LOH region on 7q31 in primary GC from China, and identified D7S486 to be the most frequent LOH locus. This study was aimed to determine what genes were affected by the LOH and served as tumor suppressor genes (TSGs) in this region. Mutation and methylation analysis were performed to explore possible mechanisms of TES inactivation in GC. Loss of heterozygosity (LOH) at specific sites of the cancer genome is considered to embody tumor suppressor genes (TSGs). We found a high frequency of LOH region on 7q31 in primary GC from China, and identified D7S486 to be the most frequent LOH locus [3]. This study was designed to explore what TSGs associated with GC were located around D7S486 in this region
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.