649PEXPRESSION OF CXCR4 IN TUMOR AND BONE MARROW OF GASTRIC CANCER PATIENTS: ASSOCIATION WITH HYPOXIA-REGULATED INDICES, DISSEMINATED TUMOR CELLS AND SURVIVAL.

+cells in GC was detected in 80% of patients with DTC in BM. Overall survival (OS) of patients with CXCR4 + -tumors was poorer than that of patients with CXCR4 � -tumors (p < 0.037). The CXCR4 + cells in BM was found in 46% of all patients, and in 56% of patients with DTC. It was also detected that CXCR4 + cells in BM in patients with M0 category was detected in 63% of patients with DTC. CXCR4 expression in BM was not associated with OS. It was evaluated that in all patients with CXCR + tumors risk of unfavorable outcome increased by more a factor of 2.82 (HR = 2.82; 95%CI 1.162– 6.832; p < 0.05). CXCR4 expression in BM was positively associated with DTC, especially in patients with M0 category. It was observed that in patients both with M0 category and CXCR4 + BM risk of unfavorable outcome increased by a factor of 3.4 (HR = 3.4; 95%CI 1.156–12.054; p < 0.03). Conclusions: CXCR4 expression in tumor was positively correlated with hypoxia and VEGF expression in tumor and OS. CXCR4 expression in BM is associated with DTC. Disclosure: All authors have declared no conflicts of interest.