Expression of heat shock proteins in osteosarcoma and its relationship to prognosis

The prognosis of osteosarcoma has been improved by chemotherapy. Heat shock proteins (HSPs) assist in folding proteins at posttranslation and degenera tion under stress. We investigated the effect of HSPs on survival in osteos arcoma. Conventional osteosarcomas of the extremities from 70 patients aged 30 year s or younger were used. Preoperational chemotherapy was performed in all ca ses. Tissues at surgery and biopsy were immunohistochemically stained with anti-HSP27, HSP47, HSP60, HSP70, HSP90 alpha, HSP90 beta, and p53 antibodie s. We classified the cases in which more than 10% of tumor cells were posit ive into the overexpressing group. Overall survival was compared between th e groups either overexpressing HSPs or not using Wilcoxon's test and Cox's proportional hazard model. The overexpression rate at biopsy was 22% (HSP27), 88% (HSP47), 66% (HSP60) , 48% (HSP70(, 47% (HSP90 alpha), 31% (HSP90 beta), and 17% (p53), respecti vely. The rate at surgery was 33% (HSP27), 94% (HSP47), 60% (HSP60), 49% (H SP70), 28% (HSP90 alpha), 40% (HSP90 beta), and 17% (p53), respectively. HSP27 and p53 overexpression at biopsy had a negative prognostic value. HSP 27 showed the strongest negative prognostic value in osteosarcoma. It is th erefore important to investigate further its function in cellular regulatio n and drug resistance.