Clinical significance of AXL kinase family in gastric cancer.

Background: We have used degenerated PCR primers designed according to the consensus kinase motifs in order to amplify expressed protein tyrosine kinase molecules from human gastric cancers. From such kinase expression profiles, we have identified more than fifty different tyrosine and serine/threonine kinases from two matched pairs of gastric cancer tissue and normal mucosa. In previous studies, we have shown the clinical significance of two tyrosine kinases identified in gastric cancer, tie-1 and mkk4. Materials and Methods: In this report, we further investigate the protein expression of the whole axl receptor tyrosine-kinase family (axl/ufo, nyk/mer and sky/rse) by immunohistochemistry and their clinicopathological associations. Results: On examination of 96 patients specimens, expression of the axl kinase family alone showed no statistical significance with respect to the patients' survival. However, the combination of nyk/mer expression with axl/ufo expression correlated inversely with the patients' prognosis result. Conclusion: This finding indicates that a co-operative relationship exists between axl/ufo and nyk/mer protein kinases and this seems to play an important role in gastric cancer progression and metastasis.