Expression analysis and prognostic significance of human kallikrein 11 in prostate cancer

Background: Kallikrein 11 (KLK11) is a newly discovered human kallikrein gene that is mainly expressed in the central nervous system and endocrine tissues. KLK11 has two alternative splicing isoforms, known as the brain type and prostate type. Many members of the human kallikrein gene family are differentially expressed in cancer and a few have potential as diagnostic/prognostic markers. Methods: In the present study, the expression of prostate type variant of KLK11 gene was analyzed by RT-PCR in 66 prostate cancer tissues. Tumors were pulverized, total RNA was extracted, and cDNA was prepared by reverse transcription. KLK11 was amplified by PCR using gene specific primers and its identity was verified by sequencing. Prostate tissues were then classified as KLK5 positive or negative based on eithidium bromide staining in agarose gels and image analysis. Results: KLK11 was found to be highly expressed in 43/66 (65%) of prostate cancer samples. We found a significant negative relationship between KLK11 expression and Gleason score (p = 0.004) and disease stage (p = 0.038). Serum total PSA concentration was found to be lower in patients with overexpression of KLK11 (p = 0.044). Conclusions: We conclude that down-regulation of the KLK11 gene in advanced and more aggressive tumors may open the possibility of being used as a future biological marker distinguishing the tumor aggressiveness as well as a useful prognostic biomarker for prostate cancer. (c) 2005 Elsevier B.V. All rights reserved

Detection of Circulating Tumor Cells in Prostate Cancer Patients: Methodological Pitfalls and Clinical Relevance

Disseminated malignancy is the major cause of prostate cancer–related mortality. Circulating tumor cells (CTCs) are essential for the establishment of metastasis. Various contemporary and molecular methods using prostate-specific biomarkers have been applied to detect extraprostatic disease that is undetectable by conventional imaging techniques, assessing the risk for disease recurrence after therapy of curative intent. However, the clinical relevance of CTC detection is still controversial. We review current literature regarding molecular methods used for the detection of CTCs in the peripheral blood and bone marrow biopsies of patients with prostate cancer, and we discuss the methodological pitfalls that influence the clinical significance of molecular staging