Janus serumbank – jakten på biomarkører for kreft

Abstract

Janus is a population-based prospective cancer biobank established in 1973. The biobank consists of residual blood serum samples from more than 300 000 men and women, who participated in different health surveys in Norway or as Red Cross blood donors during the period 1972–2004. It was established on the initiative of Professor of Pathology, Olav Torgersen (1907–78), referring to the longstanding maxim that ‘prevention is better than cure’. The purpose of the biobank was to build up a resource for studies of cancer aetiology and early detection of cancer, by measuring biochemical and immunological changes several years before the patient’s diagnosis. The Janus cohort, with comprehensive registry-based follow-up, enables longitudinal assessment of the preclinical stage in cancer patients or the latent period before the tumour has been established, and is ideal for the search of novel biomarkers of cancer. The Cancer Registry of Norway took over the cohort in 2004. In 2019 the biobank was moved into new semi-automated storage facilities and all samples were barcoded.

The biobank is annually linked to the Cancer Registry for updates on new cancer cases and by the end of 2020 the number of incident cancer cases in Janus was 107 366.

A continuous work in Janus has been on quality assurance of the biospecimens by investigating sample quality parameters like the effect of different pre-processing of the samples as well as storage time and temperature. We have investigated the stability of various hormones, proteins, metabolites, electrolytes and RNAs. This work has contributed to important knowledge in establishing Good Biobank Practice in Norway. In recent years we have also shown that the trace amounts of DNA in Janus is of sufficient quality for genotyping and methylation studies.

Today Janus is used in a large number of national and international studies and is an active part in several international cancer consortia. The scientific output from the biobank contains a substantial proportion of high impact papers that have contributed to increased knowledge on cancer biomarkers for use in cancer control. Many of the projects have focused on investigating the association between infections and cancer, environmental exposures and cancer and early detection biomarkers. In recent years we have identified RNAs as early detection and potentially screening biomarkers of cancer. We have developed and optimized an RNA sequencing method for samples with low input RNA and produced RNA profiles of pre-clinical samples from 1631 cancer patients and 673 cancer-free controls. The sequencing data is combined with detailed cancer information from the Cancer Registry of Norway and information on environmental exposures from health surveys, in advanced biocomputational analysis. Results published on the healthy control group shows that RNA expression levels are significantly affected by age and smoking. For lung cancer the results showed dynamic changes in differentially expressed circulating RNAs specific to histology and stage. In the future we aim to utilize Janus in omics analyses and produce large scale datasets that can be shared and used in many research projects.