BACKGROUND: Fewer than 20% of @entity1 with @entity3478 who are treated with surgery alone are cured. Even with the best current treatment, surgery combined with chemotherapy, only 60%-80% of @entity1 with nonmetastatic @entity3478 and 10% of @entity1 with metastatic @entity3478 are cured. Thus far, the reason for treatment failure in the nonresponding subset has not been identified. It has been hypothesized that @entity1262 , which confers multidrug resistance, might be the cause. We sought to determine whether the expression of @entity1262 is associated with poor treatment outcome in @entity421 . METHODS: In a retrospective study, we correlated @entity1262 expression with the outcome of conventional chemotherapy in 62 consecutive, clinically staged @entity1 diagnosed as having @entity421 between 1980 and 1989. RESULTS: @entity1262 was overexpressed in 27 @entity1 but not in another 34 @entity1 , and expression was ambiguous in the sample from one @entity1 . At a median follow-up of 8.9 years, the 34 @entity1 whose @entity5 did not express @entity1262 had significantly better relapse-free rates than the 27 subjects whose @entity5 expressed the protein (87% versus 0%; P<.00001) and had improved survival rates (94% versus 35%; P<.00001). Among the 46 @entity1 who received chemotherapy before surgery, the 23 whose @entity5 were negative for @entity1262 showed significantly better long-term outcomes (P<.00002), although differences in tumor @entity39 in response to therapy were only of borderline significance (P = .057). CONCLUSIONS: @entity1262 expression does correlate with treatment failure in @entity1 with @entity421 . This correlation raises the possibility that inhibiting the action of @entity1262 as part of therapy for this disease would improve outcome.

@entity1262 expression: critical determinant in the response to XXXX chemotherapy.

@entity1 :: ('9606', 'Species') :: ['patients', 'patient'] @entity1262 :: ('5243', 'Gene') :: ['P-glycoprotein'] @entity3478 :: ('MESH:D001859', 'Disease') :: ['bone cancer'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumors'] @entity39 :: ('MESH:D009336', 'Disease') :: ['necrosis'] @entity421 :: ('MESH:D012516', 'Disease') :: ['osteosarcoma']
@entity421 :: (MESH:D012516,Disease) :: ['osteosarcoma']
