Cyclooxygenase-2 (COX-2)-derived prostaglandin E 2 (PGE 2 ) plays a role in the development and progression of epithelial malignancies. Measurements of urinary PGE-M, a stable metabolite of PGE 2 , reflect systemic PGE 2 levels. Here, we investigated whether urinary PGE-M levels were elevated in healthy tobacco users and in patients with oral squamous cell carcinoma (OSCC). Median urinary PGE-M levels were increased in healthy tobacco quid chewers [21.3 ng/mg creatinine (Cr); n ¼ 33; P ¼ 0.03] and smokers (32.1 ng/mg Cr; n ¼ 31; P < 0.001) compared with never tobacco quid chewers-never smokers (18.8 ng/mg Cr; n ¼ 30). Urinary PGE-M levels were also compared in OSCC patients versus healthy tobacco users. An approximately 1-fold increase in median urinary PGE-M level was found in OSCC patients (48.7 ng/mg Cr, n ¼ 78) versus healthy controls (24.5 ng/mg Cr, n ¼ 64; P < 0.001). We further determined whether baseline urinary PGE-M levels were prognostic in OSCC patients who underwent treatment with curative intent. A nearly 1-fold increase in baseline urinary PGE-M levels (64.7 vs. 33.8 ng/mg Cr, P < 0.001) was found in the group of OSCC patients who progressed (n ¼ 37) compared with the group that remained progression free (n ¼ 41). Patients with high baseline levels of urinary PGE-M had both worse disease-specific survival [HR, 1.01 per unit increase; 95% confidence interval (CI), 1.01-1.02; P < 0.001] and overall survival (HR, 1.01 per unit increase; 95% CI, 1.00-1.02; P ¼ 0.03). Taken together, our findings raise the possibility that NSAIDs, prototypic inhibitors of PGE 2 synthesis, may be beneficial for reducing the risk of tobacco-related aerodigestive malignancies or treating OSCC patients with high urinary PGE-M levels. Cancer Prev Res; 9(6); 428-36. Ó2016 AACR.

Introduction: Field cancerization, the occurrence of transformed cells in the area adjacent to the tumor, has been attributed to the probable reasons of local recurrence of oral squamous cell carcinoma. Cancer stem cells (CSCs) have properties of tumor initiation, migration, and metastasis. The objective of the study was to evaluate their role in field cancerization. Experimental Procedure: A panel of CSCs and its related markers was established from literature and validated in i) samples from surgical margins, ii) samples from 1 cm and 2 cm distance from margin around the tumor and in additional sides. First-phase validation was done in retrospective surgical margins of tumor (N=23) by qPCR and immunohistochemistry. The best marker subset from qPCR to predict recurrence was identified by ROC curve and logistic regression analysis and validated by immunohistochemistry. The final validation is being carried out in prospective samples from tumor-adjacent normal area as mentioned above. The marker profiles were correlated with the histology of the samples and the clinical outcome of the patients on follow-up. Summary of Data: Out of 18 markers selected from literature CD44, CD147, SOX2, Snail, ATR, CyclinD1, MMP9 were selected from gene expression of first-phase validation. Among these SOX2, ATR, Cyclin D1, CD44 and CD147 were selected from IHC of first phase for second-phase validation in prospective samples (n=10) collected from 27 patients, which were clinically normal with varied grades of dysplasia; these samples were evaluated by the selected markers from the first set of validation. The correlation of markers expression with disease outcome of patients and with other clinical parameters is currently ongoing. Conclusion: Our results suggest that CSCs have role in field cancerization and might be predictive of tumor recurrence/reinitiation and/or development of second primary tumor. Citation Format: Simple Mohanta, Ravindra DR, Vikram Kekatpure, Naveen Hedne, Vijay Pillai, Shubhra Chauhan, Naveen BS, Athira Ramakrishnan, Bichu Jacob, Vishak Surendra, Leeky Mohanty, Anjana Muralidharan, Amritha Suresh, Moni Abraham Kuriakose. Cancer stem cells in field cancerization of oral squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3070.