Expression of osteopontin in different metastatic potential uveal melanoma and its significance

Abstract

Background Osteopontin is highly expressed in many metastatic tumors,but its expression in uveal melanoma and the relationship of osteopontin with metastasis is still under investigation. Objective This study was to investigate the relationship between osteopontin expression and uveal melanoma metastatic potential.Methods Fifty samples of uveal melanoma were collected in Beijing Tongren Hospital.The expressions of osteopontin in the samples were detected using immunohistochemistry,and expressions of osteopontin mRNA in different metastatic potential uveal melanoma cell lines (MU M-2B,C918,OCM-1A) were analyzed using quantitative polymerase chain reaction (Q-PCR). Results Osteopontin was positively expressed in 10 samples of 13 patients with metastasis and 14 samples of 37 patients without metastasis,showing a significant difference between them (x2=5.888,P=0.000).There were 11 samples and 13 samples exhibiting the positive expression of osteopontin in 15 epithelial type and 35 non-epithelial type of uveal melanoma respectively with the significant difference (x2=5.510,P =0.000).The positive expressing numbers of osteopontin were 20 tumors of 30 affected tumors and 4 tumors of 20unaffected ciliary tumors with the significant difference (x2 =10.470,P =0.000 ).No significant differences in the expression of osteopontige were found between different gender,age,eyes,largest basal diameters and invasion of scleral canal( P =0.536,0.256,0.802,0.848,0.555 ).The relative expression value of osteopontin mRNA was in turn 1.00±0.04,0.91 ±0.03,0.08±0.01 in MUM-2B,C918,OCM-1A with the significant difference among three cell lines( F=33.135,P＜0.05).The osteopontige mRNA expression was significant enhanced in high metastatic potentialcell lines( MUM-2B,C918 ) compared with low metastatic potential cell lines( OCM-1 A) (P＜0.05 ),but no significant difference was seen between two high metastatic potential cell lines(MUM-2B,C918) (P=0.804). Conclusions Osteopontige expression is associated with the uveal melanoma cell line invasion and metastasis potential.These results imply that osteopontige expression maybe an indicator of uveal melanoma invasion and metastasis ability. Key words: Uveal melanoma; Osteopontin; Invasion and metastasis