Prognostic implications and diagnostic significance of TFE3 rearrangement in renal cell carcinoma.

Objectives: To investigate the impact of TFE3 rearrangement, analyzing clinicopathological features that influence renal cell carcinoma (RCC) recurrence, and clarify the role of immunohistochemistry (IHC) staining in diagnosis.

Methods: We screened patients diagnosed of clear cell RCC (ccRCC), fluorescence in situ hybridization (FISH) was performed on all TFE3 positive IHC tumors. Clinicopathological and survival features were collected for analysis.

Results: Out of 695 patients treated for renal tumors, 478 (68.7%) were ccRCC and 22 were suspected of TFE3 rearrangement based on IHC. Subsequent testing revealed 8 (1.15%) were positive in the FISH test (TFE3-rearranged-RCC) and 14 (2.01%) tested negative. No significant differences were noted in general characteristics among the three groups, except for age, TFE3-rearranged-RCC were younger than ccRCC (median age, 49 vs. 58 years, p=0.02). TFE3-rearranged-RCC exhibited a significant higher recurrence rate compared to ccRCC (50% vs 18.8%) and multivariate analysis revealed that TFE3 rearrangement, along with tumor size and metastasis, was an independent prognostic factor for recurrence (HR=4.6; 95% CI 1.1-21.2; p=0.05). Survival analysis demonstrated a significant shorter PFS (progression-free survival) for TFE3-rearranged-RCC compared to ccRCC.

Conclusions: TFE3 rearrangement is an independent prognostic factor for recurrence and contributes to a worse PFS, suggesting the necessity of careful follow-up. Diagnosis should be confirmed using FISH due to low specificity of IHC. Further studies are needed to confirm TFE3 IHC staining as a prognostic factor.