Biobanking practice: RNA storage at low concentration affects integrity.

A critical issue in defining protocols for biobanking practices is the preservation of total RNA for assessing the whole transcriptome and ensuring that it can be utilized in clinically oriented studies. Storage conditions, such as temperature and the length of time that tissues and purified RNA stay frozen, may directly impact RNA preservation. In this study, we evaluated a) the quality of RNA (as measured by RNA Integrity Number) purified from head and neck tumor tissues stored at -140°C for distinct time intervals of up to 7 years, and b) the quality of their respective RNAs stored for 4 years at -80°C when diluted at either 250 ng/μL or 25 ng/μL, with repeated freezing and thawing.