Oncoprotein DEK as a tissue and urinary biomarker for bladder cancer.

BACKGROUND: Bladder cancer is a significant healthcare problem in the United States of America with a high recurrence rate. Early detection of bladder cancer is essential for removing the tumor with preservation of the bladder, avoiding metastasis and hence improving prognosis and long-term survival. The objective of this study was to analyze the presence of DEK protein in voided urine of bladder cancer patients as a urine-based bladder cancer diagnostic test. METHODS: We examined the expression of DEK protein by western blot in 38 paired transitional cell carcinoma (TCC) bladder tumor tissues and adjacent normal tissue. The presence of DEK protein in voided urine was analyzed by western blot in 42 urine samples collected from patients with active TCC, other malignant urogenital disease and healthy individuals. RESULTS: The DEK protein is expressed in 33 of 38 bladder tumor tissues with no expression in adjacent normal tissue. Based on our sample size, DEK protein is expressed in 100% of tumors of low malignant potential, 92% of tumors of low grade and in 71% of tumors of high grade. Next, we analyzed 42 urine samples from patients with active TCC, other malignant urogenital disease, non-malignant urogenital disease and healthy individuals for DEK protein expression by western blot analysis. We are the first to show that the DEK protein is present in the urine of bladder cancer patients. Approximately 84% of TCC patient urine specimens were positive for urine DEK. CONCLUSION: Based on our pilot study of 38 bladder tumor tissue and 42 urine samples from patients with active TCC, other malignant urogenital disease, non-malignant urogenital disease and healthy individuals; DEK protein is expressed in bladder tumor tissue and voided urine of bladder cancer patients. The presence of DEK protein in voided urine is potentially a suitable biomarker for bladder cancer and that the screening for the presence of DEK protein in urine can be explored as a noninvasive diagnostic test for bladder cancer.

Bladder cancer detection with urinary survivin, an inhibitor of apoptosis.

The current "gold standard" for the diagnosis of bladder cancer is cystoscopy and urine cytology. Cystoscopy, a naked eye assessment of the bladder, is invasive, uncomfortable and costly while cytology has high specificity but low sensitivity (40-60%) particularly for low-grade lesions. Therefore, there is a need for a molecular tumor marker assay that is simple to perform and sensitive, particularly for low-grade lesions. By looking to the pathophysiology of bladder cancer, we identified survivin, an inhibitor of apoptosis that is not generally expressed in fully differentiated adult tissue and is highly expressed in bladder cancer. Survivin is detected in whole urine of patients with TCC using a simple antibody based test. The sensitivity of survivin testing for new or recurrent bladder cancer is 100% while the specificity for other neoplastic and non-neoplastic genitourinary disease is 95%. The high sensitivity of this simple, noninvasive test is well suited to bladder cancer, a disease with high rates of recurrence.