Clinical Significances Of PAK5and Ezrin Expressions In Osteosarcoma

Background and purpose: PAK5is a recently identified member of PAKs. PAK5regulates many intracellular processes such as cytoskeleton remodeling, cellproliferation, cell differentiation, gene transcription and cell apoptosis. Recently, studiesfound that PAK5was overexpressed in some cancer such as gastric and colon cancer.Its role in tumorigenesis of osteosarcoma remains unclear. Ezrin is a membranecytoskeletal linker protein and it is known to be associated with metastasis of manyepithelial carcinomas such as breast and colorectal cancer, but its role in osteosarcomaalso remains unclear. The purpose of this study was to investigate the expression ofPAK5and Ezrin gene in osteosarcoma and its relationship with clinical parameters andto explore its potential clinical significance.Methods：The expressions of PAK5and Ezrin were detected in53osteosarcomabiopsied paraffin embedded samples by immunohistochemical method respectively. Therelationships between PAK5, Ezrin and clinical parameters and survival ofosteosarcoma were also analyzed.Results： The positive rates of PAK5and Ezrin protein expression inosteosarcoma tissues were81.13%and37.74%respectively. Its expressions were notrelated to clinical variables such as age, gender, histological type and local recurrence(P>0.05), but significantly related to lung metastasis (P<0.05). The positive rates ofPAK5and Ezrin protein expression in osteosarcoma tissues with lung metastasis were94.87%and46.15%respectively, significantly higher than those of non lung metastasis(42.86%and14.29%respectively). The expressions of PAK5and Ezrin had a positiverelationship to each other (P<0.05).Kaplan-Meier analysis revealed that the3-yearsurvival rate of osteosarcoma patients with PAK5positive expressions and those withnegative expressions were41.9%and88.9%respectively. The3-year survival rate ofosteosarcoma patients with Ezrin positive expressions and those with negativeexpressions were32.3%and72.7%respectively. Osteosarcoma patients with PAK5and Ezrin positive expressions had poorer prognosis than those with negative expressions ofthese two genes (P<0.01).Conclusions： There is a relationship between PAK5and Ezrin expression andlung metastasis of osteosarcoma. Both PAK5and Ezrin expressions might be potentialprognostic markers in osteosarcoma.