Comparative study of immunohistochemical analysis in tissues and molecular detection in exfoliated tumour cells in urine of human telomerase reverse transcriptase [hTERT] in urinary bladder cancer in Egyptians

ABSTRACT

Bladder cancer ranks the third most common malignancy in Egypt following to breast cancer and leukemia. Telomerase plays important roles in cancer development and promotion. Its activity is present in most human malignant tumor cells. Its activity was also detected in voided urine and in bladder washes of patients with bladder cancer, making it a potential marker for non invasive detection of bladder cancer in urine. The present study aims to correlate the expression of the hTERTmRNA in exfoliated tumour cells in urine to the in situ expression of hTERT protein in the corresponding tumour specimens and to evaluate the relationship to hTERT expression and the clinicopathologic tumour characteristics. The study comprised twenty three bladder cancer cases [22 urothelial and one squamous cell carcinomas]. Semiquantitative immunohistochemical detection of hTERT expression was evaluated using combined score evaluated by two examiners which included scoring of intensity and percentage of positivity Semiquantitative expression of hTERTmRNA relative to housekeeping gene GAPDH mRNA was evaluated from RNA extracted from exfoliated cells in urine. Expression of hTERT by immunohistochemistry [IHC] and RT-PCR was detected in 100% of the bladder cancer series. Both methods were significantly correlated [p=0.004]. There was no correlation detected between hTERT expression by both methods and clinicopathologic characteristics of the tumours represented by stage and grade. The high concordance between the semiquantitative expression of hTERT protein by IHC in tumour sections and hTERTmRNA in exfoliated tumour cells validate the potential use of hTERT as a diagnostic non invasive marker for diagnosis of bladder cancer in high risk Egyptian patients and in the follow up following cystoscopic resection of superficial tumours. To the best of our knowledge this is the first study which compares hTERT in situ expression in bladder tumours and hTERT mRNA in exfoliated tumour cells in urine