Identification of Novel Candidate Biomarkers for Oral Squamous Cell Carcinoma Based on Whole Gene Expression Profiling.

This study aimed to determine the whole gene expression profiles and to ascertain potential biomarkers for 22 oral squamous cell carcinoma (OSCC) among Thai patients using the Illumina Human HT-12, V4.0 Expression BeadChip array. Result indicated 2,724 differential expressed genes composed of 1,560 up-regulated and 1,164 down-regulated genes (unpaired t-test, p-value <0.05; fold change ≥2.0 and ≤2.0). The top 9 up-regulated genes were validated in 39 OSCC cases using TaqMan real-time quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) assay. Among these, the up-regulation of peptidase inhibitor 3 (PI3) and keratin 17 (KRT17) genes was harbored in all 39 OSCC patients (100%). Likewise, statistical analysis indicated that gene expression in 8 selective genes including keratin 16 (KRT16), keratin 14 (KRT14), keratinocyte differentiation-associated protein (KRTDAP), keratin 6B (KRT6B), PI3, S100 calcium binding protein A7 (S100A7), stratifin (SFN) and keratin 5 (KRT5) was significantly associated with well differentiated OSCC (p-value <0.05). Moreover, high level of KRT17 protein was significantly associated with well differentiated OSCC compared to moderately OSCC (p-value = 0.041). Notably, using nested-PCR analysis indicated all OSCC cases in this study were HPV-free. Especially, KRTDAP, PI3, SFN mRNA expression were first reported among patients with OSCC. Conclusion, the whole transcript expression study and TaqMan real-time qRT-PCR assay were relevant regarding the increase in gene expression in OSCC. In addition, the up-regulation of PI3 and KRT17 might constitute potential candidate molecular biomarkers to diagnose patients with OSCC.