In osteosarcoma, some studies have suggested P-glycoprotein expression is a prognostic factor. The clearance of 99mtechnetium hexakis-2-methoxyisobutylisonitrile (99mTc-MIBI) has been used in some tumor systems as an in vivo measure of P-glycoprotein-mediated efflux. In this study we explored the correlation between 99mTc-MIBI clearance and histological necrosis following induction chemotherapy and P-glycoprotein expression in osteosarcoma. The primary tumors of 20 patients with high-grade osteosarcoma were imaged at diagnosis with 99mTc-MIBI, and the uptake ratios and biological half-lives were calculated. P-Glycoprotein expression in the tumor tissue was determined immunohistochemically and by measuring mRNA expression of the multidrug resistance-1 gene. The histological necrosis following induction chemotherapy was assessed by the Huvos grading system. The biological half-life of 99mTc-MIBI ranged from 1.4 to 52.5 h. Seven of the 20 tumor samples had a favorable extent of necrosis following induction chemotherapy. The 99mTc-MIBI half-life and uptake ratio showed no correlation with histological necrosis following induction chemotherapy. The 99mTc-MIBI half-life and uptake ratio did not correlate with either measure of P-glycoprotein expression. The results of this pilot study indicate that 99mTc-MIBI imaging is not an effective predictor of histological necrosis following induction chemotherapy in high-grade osteosarcoma. 99mTc-MIBI imaging did not correlate with measures of P-glycoprotein expression in the tumor tissue.
|Original language||English (US)|
|Number of pages||6|
|Journal||Clinical Cancer Research|
|State||Published - Jan 1 2001|
ASJC Scopus subject areas
- Cancer Research