TITLE: Simple and easy method for long-term storage of human tissue for molecular analysis at room temperature
AUTHORS: Sudhir Bhatia, Gudrun Baersch

[DESCRIPTION]
The storage of human tissue at room temperature is one of challenging areas. In the literature, there is hardly any reliable method available to achieve this. We have developed a solution called Genekam Tissue Storage Solution (GTSS), which make it possible to do this task. In our laboratory, we have human tissues stored for last 5 year and GTSS is being used to isolate nucleic acid (RNA / DNA) with mini column method as well as magnetic beads isolation method. Isolated nucleic acid has been used in conventional and real time PCR along with conducting hybridization assays. This method offers the possibility for histological as well as pathological samples to be stored at room temperature. The user can transfer the samples between the laboratories at room temperature, which saves shipping costs. Our experiments show that there is no loss of nucleic acid during storage and isolated material can be used to conduct large number of molecular tests on the same sample.  Read the publication also. 

This solution is very economical in the terms of costs.

[BEFORE_START]
Read the manual and instructions carefully. 
Calculate the volume needed for storage of your tissue.
Prepare the tissue to be stored. 

[GUIDELINES]
Human tissue collection for this protocol needs prior approval by the users' institutional review board (IRB) or equivalent ethics committee(s).

[STEPS]
1. Calculate the required volume of Genekam Tissue Storage Solution (GTSS) for the sample. 15ml GTSS per 5g tissue. It is also possible to store smaller tissue, e.g. 1g or less.
    
2. Put on the gloves as for molecular analysis.
3. Label the storage tube so that it cannot fade during storage.
4. Take sterile scissors and prepare the tissue. It is best to cut the tissue into small pieces, as this can lead to better output in the long term.

Hint: If user is working under field condition to collect the samples, the whole tissue piece can be added directly to GTSS instead of making the pieces. Care must be taken that the tissue is immersed in the fluid!
5. Place the tissue pieces in a sterile tube (15ml or 50ml) using sterile forceps. 
6. Now add the calculated volumen of GTSS to the tissue pieces so that it is completely flushed through the solution (see figure below). It is very important that the tissue is completely covered with liquid. Otherwise, unpleasant odors may occur.


 


7. Now close the tubes and store them in the dark at room temperature. Don´t store in open. Avoid direct sunlight. 
8. After 2 days, you should perform a DNA/RNA isolation to determine whether the storage works. 100µl of liquid from the stored tissue is sufficient for the isolation.
9. After isolation, the isolated DNA / RNA can be measured with a spectrometer. In our isolation, we obtained up to 225ng / µl DNA or RNA per sample from such tissues. The types of isolation kits are listed as optional under Material.
10. To confirm the isolation, PCR can be performed for internal controls (house keeping genes). The PCR kits used are listed as optional under Material.
11. An important note: In our research we have found that the concentration of isolated DNA / RNA can be different in different tissues, e.g. our research shows that placental tissue contains less DNA / RNA than umbilical cord tissue.