A single-center analysis was performed to assess the significant clinical features and prognostic factors of TFE3-rearranged renal cell carcinoma (TFE3 rRCC).

The clinical data of 85 confirmed cases of TFE3 rRCC patients at the Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University from January 2007 to February 2023 were analyzed retrospectively. Among these patients, there were 39 males and 46 females, with a median age of 32 (26, 45) years. All patients underwent preoperative CT scans, 21/85 cases (24.7%) of TFE3 rRCC exhibited the characteristic feature of "circular calcification" with plain CT imaging, and enhanced CT scan showed that the tumor enhancement during the arterial phase was lower than the adjacent renal cortex. Among the 85 patients in this cohort, the median tumor diameter was 4.8(3.2, 6.5). Thirty-two patients underwent partial nephrectomy (NSS), while 51 patients underwent radical nephrectomy (RN). Two patients with distant metastasis at the time of diagnosis received only sunitinib therapy. Forty-three patients received adjuvant treatment, including 14 patients who received targeted therapy. There were 29 patients in AJCC stage Ⅲ/Ⅳ, with 10 patients presenting with venous tumor thrombus and 14 patients with lymph node metastasis. Histopathology, TFE3 immunohistochemistry, and break-apart TFE3 FISH probe detection were performed on all 85 cases, while 52 patients underwent RT-PCR and/or DNA sequencing. By combining the clinical and pathological data, we summarized the diagnostic Methods for TFE3 rRCC, evaluated the impact of surgical approaches (RN and NSS) on the survival outcomes of cT_1a/b patients, and assessed the influence of genetic subtypes (ASPL, NONO, PRCC, SFPQ, and others) on the survival outcomes of all patients. Furthermore, we analyzed the risk factors for disease progression.

TFE3 rRCC exhibited variable histopathological features, and the presence of acinar-like structures with psammoma bodies may be a relatively typical characteristic. All 85 patients showed positive TFE3 immunohistochemical staining. In 6 cases of TFE3 rRCC, break-apart TFE3 FISH probe yielded negative results. However, final confirmation was achieved through genetic sequence, with 5 cases diagnosed as NONO-TFE3 subtype and 1 case as RBM10-TFE3 subtype. Among the 85 patients, 52 underwent RT-PCR and/or DNA sequencing, revealing a total of 8 TFE3 fusion subtypes, including 11 cases of ASPL-TFE3, 8 cases of PRCC-TFE3, 10 cases of NONO-TFE3, 15 cases of SFPQ-TFE3, 1 case of CLTC-TFE3, 2 cases of LUC7L3-TFE3, 4 cases of MED15-TFE3, and 1 case of RBM10-TFE3. The survival analysis results revealed that among the 12 patients with cT_1b stage tumors who underwent radical nephrectomy (RN), the progression-free survival (PFS) was 35 (14, 109) months, which was significantly better than the NSS group (P=0.041). However, for the 14 patients with cT_1a stage tumors who underwent RN, there was no statistically significant difference in overall survival (OS) and PFS compared to the NSS group, with OS being 55(27, 134) months and PFS being 71(41, 134) months. Stratifying according to TFE3 fusion subtypes, it was found that patients with ASPL-TFE3 fusion had a significantly lower PFS compared to those with non-ASPL-TFE3 fusion subtypes (P=0.029). Survival analysis revealed that tumor diameter, surgical approach, adjuvant therapy, AJCC staging, venous tumor thrombus, and lymph node metastasis were associated with OS and PFS(P<0.05). The results of the multivariate Cox regression analysis showed that AJCC stage Ⅲ/Ⅳ(HR=2.393, 95%CI 1.418-4.039, P=0.001) and venous tumor thrombus (HR=3.543, 95%CI 1.159-10.827, P=0.026) were independent risk factors for progression-free survival (PFS).

During the non-enhanced phase of CT scan, TFE3 rRCC tumors can exhibit a circular calcification. TFE3 immunohistochemistry is an important screening method for TFE3 rRCC.Break-apart TFE3 FISH probe detection is considered the diagnostic gold standard, and gene sequencing, if feasible, can provide the subtype diagnosis of TFE3 rRCC. For cT_1a stage TFE3 rRCC, partial nephrectomy (NSS) is a viable option, while caution should be taken in selecting NSS for cT1b stage patients. Patients with ASPL-TFE3 fusion subtype have a worse prognosis. AJCC stage Ⅲ/Ⅳ and venous tumor thrombus indicate poor prognosis in TFE3 rRCC.

Carcinoma, Renal cell; TFE3 gene; Clinical characteristic