LOWER RESPONSE TO INTRAVESICAL ADJUVANT THERAPY IN HIGH-RISK BLADDER CANCER COULD BE RELATED TO THE UROTHELIAL EXPRESSION OF EGFR
Cristina Scalici Gesolfo1, Sebastiano Billone1, Alessio Guarneri1, Marco Vella1, Alessandro Perez2, Graziella Cangemi2, Antonio Russo2, Alchiede Simonato1,Vincenzo Serretta1 and GSTU Foundation3
1Section of Urology, Department of Surgical, Oncological and Stomatological Sciences, University of Palermo, Palermo, Palermo, Italy;
2Section of Medical Oncology, Department of Surgical, Oncological and Stomatological Sciences, University of Palermo, Palermo, Italy;
3Palermo, Italy
Introduction: Studies on the role of EGFR in non-muscleinvasive bladder cancer (non-MIBC) are lacking. EGFR expression has been determined mainly in tissue specimens of MIBC and its overexpression has been associated with worse prognosis and shorter survival. Urothelial EGFR status after transurethral resection (TUR) of non-MIBC could indicate the risk of recurrence and progression. We investigated the feasibility of EGFR measurement in bladder washings of patients undergoing intravesical adjuvant therapy for non-MIBC and its usefulness in identifying risk subgroups.
Patients and Methods: Our prospective study included patients after TUR of non-MIBC and healthy controls. Samples of bladder washings were centrifuged at 4˚C for 10 minutes at 1500 rpm, washed in cold phosphate buffer saline solution and centrifuged again obtaining a cellular pellet stored at −80˚C until RNA extraction was performed by miRNeasy Mini Kit (QiagenR). A Nanodrop ND-2000 spectrophotometer was used to check for good quality of RNA. RNA criteria to proceed with reverse transcription to cDNA: minimum 500 ng/ml, protein (260/280) solvents and organic compounds (260/230), contamination ratio 1.7-2.5. The cDNA obtained from RNA by High Capacity cDNA Reverse Transcription Kit (Life TechnologiesR) was used to perform a gene expression analysis by a real-time PCR, according to the method of the comparative quantification (ΔΔCt) with an endogenous control (cyclophilin). Every reaction was set in triplicate as a further guarantee of quality. The patients were grouped for EAU risk class and maintained in follow-up. EGFR expressions were statistically analyzed according to EAU risk groups and to patients’ outcomes. EGFR gene expression values were expressed in folds of change compared to healthy controls (EGFR=1).
Results: Fifty-eight patients and 21 healthy age-matched controls were entered. An adequate cellular pellet was obtained in 50 patients (86.2%) showing a median EGFR expression of 2.0-fold (IQR=0.6-4.3-fold, p=0.0004). The median level of EGFR varied considerably among the EAU risk classes. After TUR and adjuvant intravesical therapy, in 22 (55%) out of 40 high-risk patients, EGFR decreased to 1.3-fold (IQR=0.9-1.5-fold), while 18 (45%) showed elevated EGFR, median=4.7-fold (IQR=4.1-11.6-fold). At 25 months median follow-up (IQR=19.0-34.8 months), 20 (40%) patients experienced recurrence and six (12%) progression. Among patients with and those without EGFR gene increase, disease in nine (22.5%) and five (12.5%) recurred and in five (12.5%) and one (2.5%) progressed, respectively.
Conclusion: In our experience EGFR expression measurement was feasible in more than 85% of patients and was related to EAU risk classes for recurrence and progression, showing different
behavior during intravesical therapy. It was possible to identify a subgroup of high-risk patients overexpressing EGFR in spite of intravesical adjuvant therapy. EGFR evaluation in bladder washing could represent a repeatable and useful tool to identify a subgroup of patients at risk for progression predicted as not being responsive to intravesical adjuvant therapy and candidates for early radical cystectomy.
We wish to thank GSTU Foundation for data and statistical management
