Banking of fresh‐frozen prostate tissue: methods, validation and use

Abstract

The question of banking of fresh frozen human prostatic tissue is addressed by a group of authors who have compared its value with what they call “pseudobanked” tissue. They then validate their methodology by a number of methods, including expression of hepsin, which they found to be significantly higher in malignant than in benign tissue. The theme of prostate cancer is continued by an English group looking at recent trends in the use of radical prostatectomy in England, and they make a number of interesting comments about this. Again in relation to prostate cancer, a group from Boston assess the use of steroids after prostate brachytherapy to reduce the risk of acute urinary retention. Authors from McGill University, Montreal and Beth Israel in Boston, comment on the controversial areas of insulin‐like growth factor and prostatic intraepithelial neoplasia and their role in the genesis of prostate cancer. Other interesting areas such as testicular sparing surgery in testis cancer, and a comparison of hand‐assisted laparoscopic versus open radical nephrectomy, are also described in this section. OBJECTIVE To describe the establishment, methods, validation and use of a bank of fresh‐frozen human prostate tissue. MATERIALS AND METHODS On obtaining informed patient consent, protocols were followed for banking prostate tissue from any type of prostatectomy or cystoprostatectomy. A pseudobanking procedure was devised to determine the accuracy of assessing the histopathological status of the banked tissue. RNA was extracted, its quality assessed and used for quantitative real‐time reverse transcription‐polymerase chain reaction for the serine protease hepsin. RESULTS To date prostate tissue from 112 patients has been banked, with pseudobanking in 58. The histopathological assessment showed pseudobanked tissue matched adjacent unbanked tissue in 98% of cases for benign vs malignant diagnoses, and in 92% of carcinomas for the Gleason score. Hepsin expression was significantly higher in malignant than in benign tissues (P < 0.0001). CONCLUSION We established a validated method for banking human fresh‐frozen prostate tissue and applied it successfully. Hepsin expression can be used to differentiate malignant and benign prostate tissue, and as an indicator of tissue heterogeneity.

Variation in dermcidin expression in a range of primary human tumours and in hypoxic/oxidatively stressed human cell lines

“…Details of ethical approval, procedures for obtaining informed patient consent, tissue acquisition, and histopathological and molecular quality control and validation have already been described (Riddick et al, 2003). Samples of malignant prostate tissue were collected from patients undergoing radical prostatectomy or channel transurethral resection of the prostate, and non-malignant samples were obtained from patients undergoing radical cystoprostatectomy for transitional cell carcinoma of the bladder or transurethral resection of the prostate for benign prostatic hyperplasia.…”

Identification of degradome components associated with prostate cancer progression by expression analysis of human prostatic tissues

“…Detailed procedures for obtaining informed patient consent, tissue acquisition, and histopathological and molecular quality control and validation have already been described (Riddick et al, 2003). Samples of malignant prostate tissue were collected from patients undergoing radical prostatectomy or channel transurethral resection of the prostate (TURP), and nonmalignant samples were obtained from patients undergoing radical cystoprostatectomy for transitional cell carcinoma of the bladder or TURP for benign prostatic hyperplasia.…”

“…Our tissue banking technique and quality assurance procedures have been described in detail (Riddick et al, 2003). Briefly, a 9-mm Probes contain an FAM fluorescent reporter on the 5 0 end and a TAMRA quencher on the 3 0 end.…”

“…The core was divided into four quadrants prior to banking by snap freezing in isopentane supercooled in liquid nitrogen. The histopathology of tissue at the circumference of the remaining prostate from which the punch was removed was used to predict the histopathology of the banked tissue as previously validated (Riddick et al, 2003). Our expression profiling strategy has focussed on secreted proteases and their inhibitors, including 28 genes that encompass the entire human MMP and TIMP families, as well as the novel MMP inhibitor RECK.…”

Biobanking of fresh frozen tissue: RNA is stable in nonfixed surgical specimens

“…15 Immediate freezing of tissue specimens after surgery and further storage at -801C generally serve as the standard procedure for the procurement of surgical specimens. [16][17][18] A longer noncontrolled time ex vivo before freezing is believed to have significant effects on RNA integrity and mRNA expression levels and could consequently influence results in gene expression studies. This is a considerable challenge for frozen tissue biobanks and has led to laborious and expensive logistics in many projects involving biobank personnel at the surgery departments and/ or use of expensive transportation media.…”