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Summary: Early-stage oral cancer patients may have distinct clinical outcomes and respond differently to the same treatment. Up to now, there is still no individual marker to identify such patients with poor outcome. Down-regulation of a tumor suppressor gene, S100A2, in oral cancer cells was identified by mRNA profiling analysis then confirmed by RT-PCR and Southern blotting. The expression of nuclear S100A2 protein examined by immunohistochemistry was not significantly associated with any patient characteristic among the 70 early-stage oral squamous cell carcinoma (SCC) patients. Intriguingly, the loss of nuclear S100A2 positivity was significantly associated with shorter disease-free survival (p =0.019) while having no effect on the overall survival of these patients. Cox regression analysis with backward elimination identified S100A2 (p =0.006), tobacco smoking (p =0.013), and betel quid chewing (p =0.019) as independent predictors of disease-free survival. This is a first study to demonstrate that loss of nuclear S100A2 may serve as an independent prognostic marker for early-stage oral cancer patients at high risk of recurrence. A more aggressive treatment modality and intensive follow-up may be recommended for the patients with reduced expression of S100A2 in tumor cell nuclei. [Copyright &y& Elsevier]

Little is known about the specificity of angiogenic properties of oral cancer cells and the possible mechanisms. Stimulatory effects on proliferation and migration of human umbilical vein endothelial cells (HUVEC) characterized the angiogenic properties of oral cancer cells but not normal oral keratinocytes (NOK). ELISA found the presence of vascular endothelial growth factors (VEGF) both in the tested oral cancer cells and NOK. Attenuation of the proangiogenic effects by neutralizing VEGF antibodies suggests VEGF play a key role in the acquisition of the angiogenic phenotype in oral cancer cells. Western blotting of p53 and murine double mutant 2 (Mdm2) together with p53 DNA sequencing analysis indicate that p53 function loss by mutation or overexpression of Mdm2 occurred in all tested oral cancer cells regardless of their etiology. In summary, the angiogenic property of oral cancer cells is mediated by many factors in addition to VEGF and the functional status of p53. [ABSTRACT FROM AUTHOR]

Summary: Amphiregulin (AR), an epidermal growth factor (EGF)-like molecule, is a mitogen for keratinocytes. Squamous cell carcinoma (SCC) is a tumor derived from keratinoctyes. Expression of AR mRNA positively correlated with the clinical progression of 39 oral SCC. Oral SCC line, KB, was used as a model to study if increased expression of AR altered the biological behaviors of SCC cells. Exogenous AR dose-dependently enhanced the proliferation of KB cells expressing EGF receptor 1 (EGFR-1), a major receptor for AR, but little AR. Neutralizing anti-AR antibody significantly reversed the stimulatory effect of exogenous AR on KB cell proliferation. Ectopically expressed AR in stable clones manifested higher abilities to proliferate, migrate and invade Matrigel than vector control. Cyclooxygenase 2 (COX-2), but not metalloprotease 9 (MMP-9) mRNA, was increased in all the AR-expressing stable clones. In summary, AR behaves as a tumor promoter for oral SCC cells partly via increased expression of COX-2. [Copyright &y& Elsevier]

Summary: Objectives: Arginine is a nonessential amino acid which can regulate tumor growth. Argininosuccinate synthetase (ASS) is the rate-limiting enzyme for de novo arginine production. The expression pattern of ASS and the feasibility of arginine deprivation therapy in head and neck cancer have not been investigated. Materials and methods: The growth-inhibitory effect of arginine deprivation therapy was assessed either by proliferation assay with head and neck cancer cells cultured in arginine-free medium, or by tetrazolium/formazan dye assay with cells treated with an arginine-depleting drug (arginine deiminase, ADI). The tumor ASS status of 73 oral squamous carcinoma (OSCC) patients was then evaluated immunohistochemically and subsequently correlated with the corresponding clinicopathological parameters. Results: Head and neck cancer cells cultured in arginine-free medium either completely stopped proliferating, or proliferated minimally. In addition, ADI treatment inhibited the growth of all 8 head and neck cancer cell lines to different degrees. Although cellular ASS level did not correlate well with ADI-sensitivity among these cell lines, knockdown of endogenous ASS potentiated the growth-inhibitory effect of ADI in each individual cell line (FaDu and OEC-M1). In multivariable analysis, high tumor ASS level independently predicted an unfavorable disease-free survival in OSCC patients. Conclusion: High tumor ASS status is an independent variable predicting a poor disease-free survival in OSCC patients. Arginine deprivation therapy may potentially be used as a new approach to treat head and neck cancer. [ABSTRACT FROM AUTHOR]

Summary: Metastasis is a final and eventually fatal step in the progression of oral squamous cell carcinoma (OSCC) and typically accompanies a large primary tumor. Metastasis may also present from a small primary tumor and progress rapidly; therefore, early diagnosis is important for patients with small primary tumors. Galectin-1 is one significantly upregulated tumor-associated protein in many neoplasms. To determine the clinical significance of galectin-1, we analyzed its expression in clinical samples by immunohistochemistry and reverse transcription-quantitative polymerase chain reaction assay. Galectin-1 protein was significantly overexpressed in the tumor-associated stroma as well as the invasion front during early oral carcinogenesis (P <0.05). During the metastatic stage, the only significant immunoreactivity was at the tumor invasion front (P <0.05). Although galectin-1 mRNA was not significantly upregulated in the whole cancerous tissue, it was upregulated in stromal parts during early-stage OSCC and in epithelial parts at the metastatic stage. Survival analysis and a Cox’s proportional hazards model showed that synchronous upregulation of galectin-1 protein and mRNA was correlated with worse disease-free survival in early-stage OSCC (P =0.024 and P =0.047, respectively). Our findings suggest that galectin-1 upregulation at the tumor invasion front might be a predictor of early metastasis in oral carcinogenesis. [Copyright &y& Elsevier]

Summary: Gelsolin has important cellular functions, including cell motility, proliferation and apoptosis. Altered gelsolin expression has been reported in several types of human malignancies, but has not been evaluated in oral carcinogenesis. In this study, all normal oral mucosa (n =12) had high gelsolin expression, whereas only 7.7% of oral precancerous lesions (n =26) had positive gelsolin expression. A significant increased positive staining was found in primary (n =51; 37.3%) and metastatic (n =26; 30.8%) oral squamous cell carcinoma lesions. Tumors with high gelsolin expression were associated with greater tumour size (P =0.007), invasive growth (P =0.02), and younger age (P =0.006). High gelsolin expression conferred a poor clinical outcome in patients with metastatic disease (P =0.005). In conclusion, a biphasic profile in gelsolin expression was observed during the progression of oral carcinogenesis. This may be due to a balance of its multiple cellular functions in tumour invasion and cell growth. The underlying mechanisms, however, remain to be elucidated. [Copyright &y& Elsevier]

Oral cancer is one of the most common types of human cancer in the world. Although the risk factors for oral cancer are well-recognized in different countries, the molecular mechanism responsible for this malignancy remains elusive particularly in the countries where betel quid chewing is prevalent. The cDNA microarray analysis was used to analyse the mRNA expression patterns of 1177 genes in ten oral cancer patients with betel quid chewing history. Eighty-four genes involving cell adhesion, cell shape, growth, apoptosis, angiogenesis, metastasis, and metabolism were deregulated. Although the expression profile of these genes was shared by certain clinical patients, there was no significant association of the expression profile with clinical staging. Functional implication of four validated genes including caspase-1, STAT-1, COX-2 and pleiotrophin was discussed. This study provides pilot data for understanding the pathogenesis of oral cancer in countries like Taiwan where betel quid chewing is prevalent. [Copyright &y& Elsevier]