The purpose of the present study was to identify site-specific prognostic biomarkers in patients with oral squamous cell carcinoma (OSCC). For this purpose, Epidermal growth factor receptor (EGFR), Stat3, H-ras, c-myc, p53, cyclin D1, p16, Rb and Bcl-2 were localized immunohistochemically in buccal mucosa carcinoma (n=74) and tongue carcinoma (n=61) patients. Expression of markers was compared between buccal mucosa and tongue carcinoma and assessed for their prognostic value in site-specific manner. On comparison, only cyclin D1 showed significant difference in expression with higher accumulation in tongue tumors (r=+0.177, p=0.039). Moreover, univariate survival analysis showed that in buccal mucosa patients, loss of p16 and overexpression of H-ras were significant prognosticators for relapse-free survival (RFS) and overall survival (OS), respectively. However, in Cox multivariate analysis, they lost their significance after adjusting for significant clinicopathological parameters. On the other hand, in tongue cancer patients, Cox multivariate analysis showed that for RFS, Stat3 and c-myc, and for OS, Stat3, Bcl-2 and p53 were significant prognosticators after adjusting for significant confounding factors. Our findings indicated that buccal mucosa and tongue carcinoma exhibit different biological behavior which is reflected in prognosis. Therefore, this approach might be helpful to precisely identify patients for more effectively tailored treatment strategy.

Local recurrence and lymphnode (LN) metastasis are the most significant risk factors for morbidity and mortality for oral squamous cell carcinoma (OSCC) patients. In the current study, we aimed to evaluate the clinical significance of SCCAg mRNA expression in OSCC patients having histopathologically negative lymphnodes (HNLNs) and pretherapeutic peripheral blood samples (PPBs.). SCCAg mRNA was evaluated in total N=123 samples using nested RT-PCR technique. SPSS statistical software was used and p value <0.05 was considered as significant. The analysis revealed that in HNLNs, the mean ± SE for SCCAg mRNA expression was 1794.98 ± 106.67 with a median of 1488.0 while in PPBS it was 2308.27 ± 196.10 with a median of 1985.0. The frequency of SCCAg mRNA in HNLNs and in PPBs was 27% (15/55) and 29% (8/28), respectively. SCCAg mRNA expression in HNLNs and in PPBs showed a significant positive correlation with tumor size and lymphatic permeation. Multivariate survival analysis for RFS demonstrated that only SCCAg mRNA expression in HNLNs (p=0.001) and PPBs (p=0.001) were the most significant independent prognostic factors. However, for OS, multivariate analysis showed that SCCAg mRNA of HNLNs emerged at step 2 after tumor size and for PPBs it remained as single most significant independent prognostic marker. Thus, SCCAg mRNA may represent a useful tool for more accurate staging, which could improve disease management and help to obtain maximal therapeutic benefit from adjuvant therapies. Hence, SCCAg mRNA transcript could serve as a useful independent predictor of disease relapse, suggesting an increased risk of silent metastasis.