The Colorectal Cancer Tissue Bank

Background
The colorectal cancer tissue bank was established in 1999. The tissue bank embodies an infrastructure for collection of neoplastic and non-neoplastic colorectal tissues and their associated clinicopathological data. Physically, the bank is situated at the CMCC, Aarhus University Hospital, Skejby, Brendstrupgaardsvej 21, 8200 Aarhus N, Denmark. The biobank is maintained in a collaborative effort by the Colorectal Cancer Group at the Department of Molecular Medicine and following surgical departments:

• Department of Surgery, Herning Regional Hospital
• Department of Surgery, Horsens Regional Hospital
• Department of Surgery P, Aarhus University Hospital
• Department of Surgical Gastroenterology L, Aarhus University Hospital

Aim
The main purpose of the colorectal cancer tissue bank is to provide a framework for research into the molecular and cell biological aspects of colorectal cancer. Over the past years it has become evident that large well documented tissue banks are often the key to successful translation of basic research into clinical practice.

Ethics
Neoplastic tissue accepted into the colorectal cancer tissue bank originates from the healthcare activities at the hospitals associated. Tissue and clinical information is collected in accordance with standard operating procedures which guarantee ethical conduct.

These can be summarized as follows:

Patients are informed about the aim and aspects of the tissue bank both orally and in writing. Only if the patient signs an informed consent form will the patient’s tissue be accepted into the tissue bank. Patients can always withdraw their consent and their tissue will then be destroyed.

Under no circumstances may the diagnosis of a patient be compromised by collection to the tissue bank.

The patients accepted into the tissue bank are registered anonymously in a central database. Each patient is assigned a database identification code. This code is used to link the patient’s samples and clinical information. The research scientist using the tissue bank will not have access to the identity of the patients.

Information to link the database identification code with the personal identity of the patient (name, surname, and the Danish civil registry number) is saved in a separate “key” database. Only the clinicians entering the patient data into the database and the database administrator can access this “key” database.

In certain research projects, access to further data concerning the clinical history of the patient can be necessary. In such circumstances it can be requested that the database manager seeks to collect this additional information.

The tissue bank has been approved by the Danish Scientific Ethical Committee.

Data security

The tissue bank database has been developed with special attention to data security.
Strict procedures regulate access to stored information. These include user authorization, database user groups with different security levels, limitation on failed attempts to database access, user records, database logging, and trained IT-staff and physical measures to increase data security.
Data security and integrity is ensured through back up routines and maintainance procedures, including server RAID and tape backup.

The tissue bank database has been approved by the Danish Data Protection Agency.

What is collected
The aim of the colorectal cancer tissue bank is to acquire neoplastic and control non-neoplastic material from patients with all types of colorectal neoplasias. By 2010, the colorectal cancer tissue bank holds more than 23,000 samples (adenomas, adenocarinomas, liver metastases, normal mucosa, and blood) from more than 2,000 patients. Roughly 350 new patients are added to the bank each year.

In collaboration with the relevant pathological departments the pathological information associated with the collected tissues is entered into the database. Manual and automatic procedures ensure that clinical follow up information for the individual patients is continuously collected and stored in the database.

Tissue collection
Tissue and blood is collected at the following sites:

• Department of Surgery, Herning Regional Hospital
• Department of Surgery, Horsens Regional Hospital
• Department of Surgery P, Aarhus University Hospital
• Department of Surgical Gastroenterology L, Aarhus University Hospital

Technical staff is permanently present at the Surgical departments to ensure optimal and immediate handling of the resected tissue. In this way mRNA expression artifacts due to hypoxia etc. are minimized. When possible, biopsies are collected from the tumor as well as from the normal mucosa. Importantly, tumor areas appearing ischemic and/or necrotic are avoided during the biopsy process. Blood is collected from all patients entering the tissue bank.
The collected biopsies are labeled with database generated identification codes and flash frozen in liquid nitrogen within 20 minutes of the resection. Solid tissue is stored in three different formats: fresh frozen, Tissue Tek embedded, and embedded in an RNA preserving reagent.

The frozen neoplastic and non-neoplastic tissue is stored in -80°C freezers at the CMCC freezer facility. Here, special security measures are taken to avoid thawing and/or exposure to large changes in temperature. All freezers containing tissue are included in Aarhus University Hospital’'s secure electricity supply and monitored by a triple layer alarm system.
It is not within the scope of the colorectal cancer tissue bank to store formalin fixed and paraffin embedded tumor tissue. However, tumor tissue in this format can be obtained through collaboration with the Pathological Department THG at Aarhus Hospital.
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Downstream tissue applications
The flash frozen solid tissue samples are stored as they are. In contrast, blood samples are processed immediately upon arrival. Half the blood sample is frozen directly, and from the other half, plasma and DNA is extracted. Thus, the tissue bank holds readily available blood, plasma, and DNA from all patients.
Only in relation to specific research projects are DNA, RNA and proteins isolated from the solid tissue, however when available these molecules are also registered and stored in the tissue bank.

Quality Control
All RNA samples are analyzed using the Bioanalyzer from Agilent and the RNA quality measures such as the 18S/28S ratio and the RNA integrity number (RIN) are stored with the samples in the database.

Periodic quality controls of the procedures used for collection of tissue and clinical information and for the associated database are being carried out with the aim of avoiding possible breakdown in the system.

These controls specifically monitor:
- Identification and management of samples.
- Suitability of the acquisition and freezing protocols.
- Equipment Maintenance.
- Validation of data.
- Access code control.