Telomerase activity, cytokeratin 20 and cytokeratin 19 in urine cells of bladder cancer patients

الملخص EN

Aim of the Study : This work aims to search for markers suitable for the screening of bladder cancer, which should be specific, sensitive, reproducible, non-invasive and at acceptable cost.

Patients and Methods : The study included 50 patients diagnosed as bladder cancer (35 TCC, 15 SCC) of different stages and grades, 30 patients with various urothelial diseases, besides 20 apparently healthy subjects of matched age and sex to the malignant group.

A random midstream urine sample was collected in a sterile container for the determination of telomerase by RT-PCR, keratin 19 by ELSA CYFRA 21-1 IRMA kit, keratin 20 by RT-PCR and immunohistochemical staining, and urine cytology.

Results : For all parameters (telomerase, K19, K20 and cytology) the malignant group was significantly different from both the benign and the control groups.

None of the four studied parameters was correlated to the stage of the disease, and when it comes to grade, only K19 showed a significant positive correlation with grade both in TCC and SCC.

When ROC curves for all parameters were compared, K19 had the largest area under the curve, and then comes K20.

Conclusion : • K 19 may be used as a biological marker for the diagnosis of bladder cancer.

K19 could not be used for differential diagnosis of different types of bladder cancer, meanwhile it could be a marker for differentiation that decreases in less differentiated tumors.

• As a tumor marker, K20 reflects inability to differentiate tumor type or grade in TCC, while in SCC of the bladder it is correlated with the grade.

• As a method, RT-PCR is superior to immunostaining for the detection of bladder cancer, meanwhile K20 immunohistochemistry (IHC) results were much better than urine cytology as a bladder cancer screening test.

• Haematuria and inflammation reduced the specificity of telomerase assay, which reduced its validity as a tumor marker of bladder cancer.

• K19 and K20 are the best candidates as screening tests for the diagnosis of bladder cancer, representing the highest sensitivity and specificity, beside the radiological and histopathology.

Meanwhile, telomerase, although it was a sensitive enough marker, it reflected a high false positive rate.