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Published on: July 28, 2010
Mutations in the ST7/RAY1/HELG locus rarely occur in primary colorectal, gastric, and hepatocellular carcinomas
S Yoshimura1, T Yamada, S Ohwada
1Second Department of Surgery, Gunma University Faculty of Medicine, 3-39-15, Showa-machi, Maebashi, Gunma 371-8511, Japan.
Abstract:
Human cancers frequently show a loss of heterozygosity on chromosome 7q31, which indicates the existence of broad-range tumour-suppressor gene(s) at this locus. Truncating mutations in the ST7 gene at this locus are seen frequently in primary colon cancer and breast cancer cell lines. Therefore, the ST7 gene represents a novel candidate gene for the tumour suppressor at this locus. However, more recent studies have reported that ST7 mutations are infrequent or absent in primary cancer and cell lines. To ascertain the frequency of mutations of the ST7 gene in cancer cells, we examined mutations in the ST7 coding sequence in 48 colorectal, 48 gastric, and 48 hepatocellular carcinomas using polymerase chain reaction-single-strand conformational polymorphism and direct sequencing. We detected somatic mutations, which were located near the exon-intron junction in intron 8, in only three out of 144 cases. We conclude that mutations in the ST7 gene are rare in primary colorectal, gastric, and hepatocellular carcinomas.
Insights
The ST7 gene was investigated as a potential tumor suppressor. Mutations in ST7 were found to be rare in colorectal, gastric, and hepatocellular carcinomas, suggesting it is not a major driver of these cancers.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Loss of heterozygosity on chromosome 7q31 suggests tumor suppressor genes.
- The ST7 gene was initially proposed as a candidate tumor suppressor based on mutations in colon and breast cancer cell lines.
Purpose of the Study:
- To determine the frequency of ST7 gene mutations in primary colorectal, gastric, and hepatocellular carcinomas.
- To clarify the role of ST7 as a tumor suppressor in these specific cancer types.
Main Methods:
- Analysis of ST7 coding sequences in 144 primary tumor samples (48 colorectal, 48 gastric, 48 hepatocellular).
- Utilized polymerase chain reaction-single-strand conformational polymorphism (PCR-SSCP) and direct sequencing.
- Somatic mutations were identified and localized.
Main Results:
- Only three somatic mutations in the ST7 gene were detected across all 144 samples.
- The identified mutations were located near the exon-intron junction of intron 8.
- The overall mutation frequency was very low in the studied primary carcinomas.
Conclusions:
- Mutations in the ST7 gene are infrequent in primary colorectal, gastric, and hepatocellular carcinomas.
- The ST7 gene is unlikely to be a frequently mutated tumor suppressor in these cancer types.
- Further research may be needed to fully elucidate the role of ST7 in tumorigenesis.
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