Our results indicated that positive RMS samples to mdr1 show higher HLA class I expression than those which were negative to mdr1 PCR, what indicates a significant correlation between the expression of both molecules.
The statistical analysis of results showed that the cases of tetraploid and/or multiploid RMS, overexpressing p53 (W&M and mutated) and MDR-1, were characterized by an overall worse prognosis.
The pattern of resistance and the level of P-glycoprotein expression were similar to those found in the resistant RMS TE.32.7.DAC cell line obtained in vitro.
The TE.32.7-DAC-resistant cell line exhibited cross-resistance to vincristine and doxorubicin and showed mdr1/P-glycoprotein over-expression, suggesting that this mechanism was involved in the reduction in intracellular drug concentration and may be responsible for the failure of treatment of RMS with classical cycles of cytotoxics.