UROTHELIAL EGF-R GENE EXPRESSION IN BLADDER WASHINGS: A FEASIBILITY STUDY

Risultato della ricerca: Other

Abstract

Introduction and Objectives: Epidermal growth factor (EGF)is a strong tumor promoter. Its concentration is reduced inurine of patients affected by bladder cancer supporting theimportant role of its interaction with the urothelial epidermalgrowth factor-receptor (EGF-R) in tumor development andprogression (1, 2). It would be of great usefulness to evaluateEGF-R gene expression during follow-up of non-muscleinvasive bladder cancer (NMI-BC) avoiding tissue biopsy.The objective of our research was to investigate thefeasibility of EGF-R evaluation in bladder washings ofpatients affected by NMI-BC. Materials and Methods: Thestudy included patients undergoing adjuvant intravesicaltherapy for NMI-BC and age-matched healthy controls. In apreliminary phase of our research, bladder washing wasselected for EGF-R analysis due to the high variability andeasier contamination of urine. Samples of bladder washingswere collected before, during and after adjuvant intravesicaltherapy and during the follow-up to investigate the geneexpression of EGF-R. After collection, the samples werecentrifuged twice at 4˚C, 1,200 rpm for 10 minutes, in coldphosphate-buffered saline solution. The cellular pellet wasstored at –80˚C and later analyzed by isolation of cellularRNA using a miRNeasy Mini Kit (Qiagen®). Reversetranscription-polymerase chain reaction (RT-PCR) wasperformed in order to analyze EGF-R gene expression.Changes in the EGF-R content were calculated using theooCt method after normalization with endogenous referenceand calibrating cycle threshold (Ct) value for each RNAobtained for triplicate reactions. The percentage of patientswith bladder washings giving a useful pellet for EGF-Rdetermination was considered for the feasibility. EGF-R geneexpression was related to tumor characteristics and comparedto healthy controls. Descriptive statistical analysis wasperformed. Results: Thirty-two patients and 13 healthycontrols were entered in the study. Fifty-two samples wereobtained. A useful pellet to evaluate EGF-R expression wasobtained in 26 patients (81.2%), 22 males and 4 females,mean age 71 (range=52-83) and in 10 healthy controls(76.9%). The bladder tumors were Ta, T1 and Tis,respectively in 8, 16 and 2 patients; single in 7 and multiplein 17, primary in 11 and recurrent in 16 patients. In 6 patients, a synchronous Tis was diagnosed. The median EGFRexpression resulted 2.4-fold compared to controls (EGFR=1). Four patients (15%) presented elevated levels of EGFRafter transurethral resection (TUR) and before adjuvanttherapy with a median value of 4-fold. EGF-R expressionincreased during follow-up in 9 patients (34%) with a medianof 4-fold (range=2.5-8); returning within limits in 3 of themafter adjuvant therapy. Discussion: EGF-R is detected in thebasal layer of normal urothelium. Its expression in NMI-BCis limited and increases in high grade and invasive tumors.EGF-R activation promotes tumor growth by blockingapoptosis and increasing cell proliferation, motility, adhesionand invasive capacity. The results obtained in NMI-BC onEGF-R as an independent predictor of progression are scarceand conflicting (1). Only few data have been obtained inNMIBC (2). Our study suggests the feasibility of EGF-Revaluation in bladder washings of patients affected by NMIBCavoiding tissue biopsies. It was technically possible toevaluate its expression after TUR in more than 80% of ourpatients resulting up-regulated in 15% of them. EGF-R upregulationmight represent a marker of potentialaggressiveness of the tumor, failure of the treatment andprogression during follow-up.
Lingua originaleEnglish
Pagine3674-3675
Numero di pagine2
Stato di pubblicazionePublished - 2015

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