A9 region in EPHB2 mutation is frequent in tumors with microsatellite instability. Analysis of prognosis.

ABSTRACT

AIM: The aim of the present study was to determine the relation of EPH tyrosine kinase receptor B2 (EPHB2) A9 region mutation and microsatellite instability (MSI); and to analyze their influence in prognosis of patients with sporadic colorectal cancer (CRC). PATIENTS AND METHODS: A total of 481 patients with CRC were examined. MSI (NCI criteria) and EPHB2 were analyzed using PCR and fragment analysis software. RESULTS: EPHB2 mutation was detected in 3.1% of patients. Mutation of EPHB2 was associated with location and with MSI status. We considered low instability (L-MSI) when only one marker showed instability, high instability (H-MSI) when two or more markers were positive and microsatelllite stable (MSS) when no instability was detected. The stratified analysis of overall survival (OS) and disease-free survival (DFS) in MSI according to EPHB2 status revealed no statistically significant differences. However, the risk of recurrence of H-MSI tumors with EPHB2 mutation carriers was 3.6-times higher than in non-mutation carriers. CONCLUSION: The frequency of EPHB2 mutation is higher in patients with H-MSI than MSS tumors. Promising results were found regarding the prognostic influence of EPHB2 in H-MSI.