Tissues from routine pathology archives are suitable for microRNA analyses by quantitative PCR.

BACKGROUND: MicroRNAs have recently taken centre stage as short non-coding RNAs that regulate mRNA expression. AIM/METHODS: To assess the feasibility of using microRNA techniques on routinely processed tissues, the accessibility of two representative microRNAs was examined by real-time quantitative PCR in 86 human formalin-fixed paraffin-embedded (FFPE) samples from liver, breast, bone marrow, lymphatic tissues and colon. Murine liver was used to analyse the influence of fixation time and different fixatives. RESULTS: High-quality microRNA was successfully extracted from routinely processed formalin-fixed tissues, resembling PCR amplification results from snap-frozen material analysed in parallel. While fixation time did not affect microRNA accessibility, non-buffered formalin or fixative supplements such as glutaraldehyde influenced PCR results. Storage of human tissues for up to 7 years did not cause a significant deterioration of microRNA. However, microRNA quality in human archival material following routine processing 10-20 years ago was decreased. Oxidation by ambient air during storage and fixation in non-buffered formalin is a possible reason for loss of microRNA quality. CONCLUSION: The assessment of microRNAs in readily obtained formalin-fixed paraffin-embedded samples is a highly promising tool in molecular pathology when similarly treated samples are analysed. Therefore, microRNA analyses will gain wider acceptance as an adjunct to morphological tissue assessment in routine pathology and retrospective studies.

Retrospective analysis of prognostic factors after liver resection and transplantation for cholangiocellular carcinoma.

BACKGROUND: Cholangiocellular carcinoma is an uncommon primary liver cancer, which may be mixed with hepatocellular carcinoma. A retrospective analysis was undertaken to evaluate the results of surgical treatment and to identify prognostic factors. METHODS: Between 1978 and 1996, 162 patients underwent surgery for cholangiocellular carcinoma: liver resection (n = 95), liver transplantation (n = 24) and exploratory laparotomy with and without drainage (n = 43). Univariate and multivariate analyses of prognostic factors were performed. RESULTS: Overall survival was 47 per cent at 1 year, 28 per cent at 2 years and 13 per cent at 5 years. Survival rates for patients with resectable tumours were 64, 43 and 21 per cent respectively, and for those who underwent liver transplantation 21, 8 per cent and zero respectively. Univariate analysis showed that the following variables had an effect on survival: age, jaundice, liver resection, T, N and M stage in the tumour node metastasis classification, Union Internacional Contra la Cancrum (UICC) tumour stage, tumour-free margins, vascular infiltration, tumour number, tumour size and serum level of carcinoembryonic antigen. Multivariate analysis identified jaundice, N and M category, and UICC tumour stage as independent prognostic factors. CONCLUSION: The data underscore the importance and prognostic value of the UICC tumour classification for cholangiocellular carcinoma. The prognosis of mixed tumours is no different. Liver resection remains the treatment of choice; transplantation offers no solution for otherwise unresectable tumours.