Frozen section histopathology and preanalytical factors affecting nucleic acid integrity in biobanked fresh-frozen human cancer tissues.

BACKGROUND

In this study, we evaluated the effects of storage duration and ischemic time on nucleic acid quality of fresh-frozen tissue (FFT) from colon adenocarcinoma (COAD), hepatocellular carcinoma (HCC), and renal cell carcinoma (RCC) collected at the Cancer Tissue Bank of Seoul National University Hospital.

METHODS

A total of 102 FFT samples were analyzed to compare DNA integrity number (DIN) and RNA integrity number (RIN) according to storage duration and ischemic time. Additionally, the effects of histopathologic features-such as tumor cell proportion, inflammatory cell infiltration, and stromal fibrosis-on nucleic acid quality were evaluated.

RESULTS

DIN and RIN remained stable overall even though the storage duration increased, with no statistically significant differences observed. In particular, there was almost no decrease in RNA quality in HCC and RCC samples, but in COAD samples, RIN tended to decrease slightly as the storage duration increased. No significant difference was confirmed between ischemic time and nucleic acid quality, but in COAD tissue, RNA quality variability tended to increase as the ischemic time increased. Furthermore, RIN increased as the tumor cell proportion increased, whereas inflammatory cell infiltration and extracellular mucin pool were identified as independent negative predictors of RIN.

CONCLUSIONS

This study confirmed that nucleic acid integrity can be maintained even during long-term storage of FFT and demonstrated that histologic features are closely related to RNA quality. This study would contribute to the establishment of quality assessment and management standards for biobank FFT samples.