Biobanking of Fresh-Frozen Gastric Cancer Tissues: Impact of Long-Term Storage and Clinicopathological Variables on RNA Quality.
Author(s): Zhang X, Han QY, Zhao ZS, Zhang JG, Zhou WJ, Lin A
Publication: Biopreserv Biobank, 2019, Vol. 17, Page 58-63
PubMed ID: 30457887 PubMed Review Paper? No
Purpose of Paper
This paper investigated the effects of patient age, gender, tumor location, estimated blood loss, surgical procedure type, warm ischemia time, cold ischemia time, and up to 12 years of frozen storage on tissue morphology and RNA integrity in gastric cancer specimens. Correlations between RNA integrity number (RIN) and tumor cell percentage, stroma percentage, cellularity, and necrosis extent were also examined.
Conclusion of Paper
RIN values were not significantly correlated with frozen storage duration, patient age, gender, tumor location, estimated blood loss, surgical procedure type, warm ischemia time, or cold ischemia time. While RINs were not influenced by cellularity or percentage necrosis, RIN and tumor cell percentage were significantly correlated with higher RINs in specimens with higher tumor content and lower RINs in tissues with higher stromal content.
Studies
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Study Purpose
This study investigated the effects of patient age, gender, tumor location, estimated blood loss, surgical procedure type, warm ischemia time, cold ischemia time, and up to 12 years of frozen storage on tissue morphology and RNA integrity in gastric cancer specimens. Correlations between RIN and tumor cell percentage, stroma percentage, cellularity, and necrosis extent were also examined. Gastric cancer tissue specimens were collected from 90 patients undergoing surgery (84 not treated with chemotherapy or radiotherapy, 6 treated with neoadjuvant chemotherapy before surgery) and transported at room temperature to the pathology laboratory. Tumor tissues were divided into three pieces using the mirror image technique. One piece was immediately fixed in formalin and paraffin embedded (details not provided) and slides were prepared of 4 µm-thick sections, stained with hematoxylin and eosin (H&E), and reviewed independently by two pathologists. The remaining two tissue pieces were snap-frozen in liquid nitrogen and stored at -80°C for up to 12 years. Frozen specimens were ground with a mortar and pestle under liquid nitrogen and RNA was extracted using a phenol-chloroform method. RNA was quantified by a spectrophotometer and RIN was determined with a bioanalyzer.
Summary of Findings:
The mean RIN of the tumor specimens was 6.58 ± 1.71 and 86.7% (78/90) of specimens had a RIN ≥5 and 81.1% (73/90) had a RIN ≥6. There was no correlation between storage duration and RIN values (P=0.755). While RINs were not influenced by cellularity (P=0.48) or percentage necrosis (P=0.415), there was a weak significant correlation between RIN and tumor cell percentage (r=0.385, P=0.002) and a weak inverse correlation was found between RINs in tissues with higher stromal content (r= -0.324, P=0.011). No statistical significance was found between RIN and patient age, gender, tumor location, estimated blood loss, surgical procedure type, warm ischemia time, or cold ischemia time.
Biospecimens
Preservative Types
- Frozen
Diagnoses:
- Neoplastic - Carcinoma
Platform:
Analyte Technology Platform Morphology H-and-E microscopy RNA Spectrophotometry RNA Automated electrophoresis/Bioanalyzer Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Preaquisition Patient age ≤66 y
>66 y
Preaquisition Patient gender Female
Male
Preaquisition Blood loss amount ≤150 mL
>150 mL
Preaquisition Surgical procedure type Laparotomy
Laparoscopy-assisted
Preaquisition Warm ischemia time ≤3 h
>3 h
Biospecimen Acquisition Biospecimen location cardia
body
antrum
Biospecimen Acquisition Cold ischemia time ≤20 min
20-40 min
Biospecimen Aliquots and Components Biospecimen components Tumor content
Stromal content
Cellularity
Percentage necrosis
Storage Storage duration 1 year
2 years
3 years
4 years
5 years
6 years
7 years
8 years
9 years
10 years
11 years
12 years
Biospecimen Aliquots and Components Biospecimen heterogeneity A range of tumor cell contents examined