[693] Osteopontin Overexpression Is Associated with Improved Survival Time in Patients with Gastric Adenocarcinoma.

Jonathan B Rock, Ioannis S Hatzaras, Mark P Bloomston, Wendy L Frankel. The Ohio State University Medical Center, Columbus

Background: Osteopontin (OPN) is an important mediator in tumor progression in several cancers. Through its interactions with CD44 and Integrins, OPN enhances the ability of tumor cells to metastasize, however, regulatory mechanisms are poorly understood. Alterations in p53 are well known factors in tumorigenesis. We evaluated the expression of OPN, CD44, and p53 and their association with outcome in gastric adenocarcinoma.
Design: Gastric adenocarcinomas (159) with available tissue and clinicopathologic data including patient age, gender, tumor grade and outcome were reviewed. Tissue microarrays with 1 mm cores were constructed, stained with antibodies for OPN, CD44 and p53, and graded as strongly positive (2), weakly positive (1) and negative (0). Controls were adjacent uninvolved stomach in 30 cases. Statistical analysis was performed using student's t-test, Chi-Square, Logistic Regression Analysis for correlation with differentiation and Cox proportional hazards analysis for survival.
Results: There was no association between patient age, gender or any marker and poor tumor differentiation. Expression of OPN, CD44 and p53 in tumors is shown in the table. Controls were negative with all markers.

OPN, CD44 and p53 Staining in Tumors

	Negative	Weak	Strong
OPN	50 (31.4%)	61 (38.4%)	48 (30.2%)
CD44	59 (37.1%)	46 (28.9%)	54 (34.0%)
p53	66 (41.5%)	33 (20.8%)	60 (37.7%)

Expression of p53 correlated with both OPN (P=0.03) and CD44 (P=0.002), while OPN and CD44 were not associated with each other. By multivariate analysis, poor differentiation was associated with shorter survival with Hazards ratio of 1.93 (95% CI 1.26, 2.95; P=0.002). Negative and weak expression of OPN was associated with shorter survival with Hazards ratio of 1.79 (95% CI 1.08, 2.94; P=0.002) and 1.97 (95% CI 1.23, 3.18; P=0.005), respectively.


Conclusions: Although OPN and CD44 were associated with p53, they did not correlate with each other suggesting complex interactions in gastric adenocarcinoma. Surprisingly, our results suggest that strong OPN expression in gastric adenocarcinoma was associated with longer survival. Additional studies may help elucidate the role of OPN in tumorigenesis.
Category: Gastrointestinal

Tuesday, March 1, 2011 9:30 AM

Poster Session III # 151, Tuesday Morning