Methylation screening of the <it>TGFBI </it>promoter in human lung and prostate cancer by methylation-specific PCR

• Main Authors: Shao Genze, Shah Jinesh N, Hei Tom K, Zhao Yongliang
• Format: Article
• Language: English
• Published: BMC 2008-10-01
• Series: BMC Cancer
• Online Access: http://www.biomedcentral.com/1471-2407/8/284

<p>Abstract</p> <p>Background</p> <p>Hypermethylation of the <it>TGFBI </it>promoter has been shown to correlate with decreased expression of this gene in human tumor cell lines. In this study, we optimized a methylation-specific polymerase chain reaction (MSP) method and investigated the methylation status of the <it>TGFBI </it>promoter in human lung and prostate cancer specimens.</p> <p>Methods</p> <p>Methylation-specific primers were designed based on the methylation profiles of the <it>TGFBI </it>promoter in human tumor cell lines, and MSP conditions were optimized for accurate and efficient amplification. Genomic DNA was isolated from lung tumors and prostatectomy tissues of prostate cancer patients, bisulfite-converted, and analyzed by MSP.</p> <p>Results</p> <p>Among 50 lung cancer samples, 44.0% (22/50) harbored methylated CpG sites in the <it>TGFBI </it>promoter. An analysis correlating gene methylation status with clinicopathological cancer features revealed that dense methylation of the <it>TGFBI </it>promoter was associated with a metastatic phenotype, with 42.9% (6/14) of metastatic lung cancer samples demonstrating dense methylation vs. only 5.6% (2/36) of primary lung cancer samples (<it>p </it>< 0.05). Similar to these lung cancer results, 82.0% (41/50) of prostate cancer samples harbored methylated CpG sites in the <it>TGFBI </it>promoter, and dense methylation of the promoter was present in 38.9% (7/18) of prostate cancer samples with the feature of locoregional invasiveness vs. only 19.4% (6/31) of prostate cancer samples without locoregional invasiveness (<it>p </it>< 0.05). Furthermore, promoter hypermethylation correlated with highly reduced expression of the <it>TGFBI </it>gene in human lung and prostate tumor cell lines.</p> <p>Conclusion</p> <p>We successfully optimized a MSP method for the precise and efficient screening of <it>TGFBI </it>promoter methylation status. Dense methylation of the <it>TGFBI </it>promoter correlated with the extent of <it>TGFBI </it>gene silencing in tumor cell lines and was related to invasiveness of prostate tumors and metastatic status of lung cancer tumors. Thus, <it>TGFBI </it>promoter methylation can be used as a potential prognostic marker for invasiveness and metastasis in prostate and lung cancer patients, respectively.</p>