Discordant Protein- and Transcript-Level Expression of TRAF7 and the EDA2R–Apoptotic Axis in Clear Cell Renal Cell Carcinoma
Matea Buljubašić Franić, Tonka Mateljak, Lara Smoljo, Petar Todorović, Anita Racetin, Petar Đolonga, Danijel Antonio Grubišić, Lucija Bavčević, Julie Costet, Sandra Kostić, Katarina Vukojević, Nela KelamBackground/Objectives: Clear cell renal cell carcinoma (ccRCC) is characterized by dysregulated apoptotic and inflammatory signaling, yet the tissue-level behavior of several candidate regulators remains poorly defined. Materials and Methods: We quantified ectodysplasin A2 receptor (EDA2R), TNF-receptor-associated factor 7 (TRAF7) and the apoptotic fragments cleaved-PARP1 and cleaved-CASP3 by immunofluorescence in 49 ccRCC and 27 matched non-tumoral cortex samples and analyzed the corresponding transcripts in TCGA-KIRC and GTEx. Results: TRAF7 protein was higher in tumor than in control tissue (median 0.81% vs. 0.63% positive area, p = 0.015), an increase concentrated in grade 2–3 tumors, whereas EDA2R and the apoptotic fragments did not differ (all p > 0.59). The positive EDA2R–cleaved-PARP1 correlation in low-grade tumors (ρ = +0.54, p = 0.002) was attenuated in high-grade tumors (ρ = +0.06, p = 0.84). In TCGA-KIRC, EDA2R mRNA was overexpressed in tumors, and higher expression was associated with better overall survival (HR = 0.60, p = 0.0011), including after mutual adjustment for the four transcripts (HR = 0.66, p = 5.3 × 10−5) and after adjustment for age, sex, stage and grade (HR per standard deviation = 0.83, p = 0.008). TRAF7 mRNA did not differ between tumor and normal tissue, but higher levels were associated with worse overall survival after the same adjustment (HR = 1.38, p < 0.001). Conclusions: TRAF7 and EDA2R show opposite, marker-specific discordance between protein- and transcript-level data across cohorts, consistent with, but not demonstrating, regulation beyond transcription. EDA2R is a candidate transcript-level prognostic marker requiring validation, and TRAF7 is a protein-level feature of ccRCC; paired RNA–protein and functional studies are needed.