We retrospectively analyzed 30 cases of ARMS in Mexican patients and evaluated the fusion status of the genes using RT-PCR and fluorescence in situ hybridization (FISH) in formalin-fixed paraffin-embedded tissues (FFPET).
From 25 samples (83 % ) with optimal RNA quality, RT-PCR revealed 15 cases (50 % ) with the t(2;13)/PAX3-FKHR. Only one case (3 % ) was positive to t(1;13)/PAX7-FKHR and nine cases (30 % ) were fusion-negative. Correspondingly, using FISH, the t(2;13)/PAX3-FKHR was found positive in 19 cases (63.5 % ), one case (3 % ) revealed the t(1;13)/PAX7/FKHR and ten cases (33.5 % ) were fusion-negative by this method. Five cases were not evaluable by RT-PCR but recovered by FISH. Only four of the total revealed t(2;13); the other was fusion-negative.
FISH technique is more sensitive when FFPET is used to describe the chromosomal translocation of ARMS. These Latino patients showed an association of the t(2;13) in older patients (mean: 9 years) and negative translocation in younger patients (mean: 4 years) (p <0.05). Both t(2;13) and negative-fusion were present in patients with clinical stages III and IV (p <0.05). There was a nonsignificant trend of t(2;13) to lower overall survival than negative-fusion status.