Downregulation of Tumour Suppressor Gene TSLC1 mRNA in Human Oral Squamous Cell Carcinoma

Abstract

Objectives: To identify changes in the expression patterns of the TSLC1 (tumour suppressor in lung cancer 1) gene family in oral squamous cell carcinoma.Materials and Methods: DNA microarray was performed to analyse gene expression of the TSLC1 gene family in oral squamous cell carcinoma—derived cell lines (HSC2, HSC3, Ca9-22, and Sa3) when compared with normal oral keratinocytes using high-density Affymetrix U133 plus 2.0 GeneChip arrays containing 54,675 probe sets. Comparison of TSLC1 mRNA expression levels between 30 primary oral squamous cell carcinomas and normal tissues was performed by real-time quantitative reverse transcriptase polymerase chain reaction, which was used to confirm the microarray results.Results: Microarray analysis demonstrated TSLC1 expression levels that were downregulated at least 2-fold or more in 3 of 4 oral squamous cell carcinoma-derived cell lines (75%) compared with normal oral keratinocytes. Significant downregulation of TSLC1 expression levels was shown by real-time quantitative reverse transcriptasepolymerase chain reaction analysis in all oral squamous cell carcinoma—derived cell lines and 23 (77%) of 30 primary oral squamous cell carcinomas (p < 0.01, Mann-Whitney U test), consistent with the microarray data.Conclusions: These results suggest that the TSLC1 gene is frequently altered in oral squamous cell carcinoma. This alteration may contribute to carcinogenesis in oral cancer.