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Updated: May 17, 2026
A Quantitative Detection Method for MicroRNAs in the Kidney of an Ischemic Kidney Injury Mouse Model
Published on: September 11, 2020
Impact of ischemia and procurement conditions on gene expression in renal cell carcinoma
Nick W Liu1, Thomas Sanford, Ramaprasad Srinivasan
1Urologic Oncology Branch, National Cancer Institute, NIH, Bethesda, MD, USA.
Purpose:
Previous studies have shown that ischemia alters gene expression in normal and malignant tissues. There are no studies that evaluated effects of ischemia in renal tumors. This study examines the impact of ischemia and tissue procurement conditions on RNA integrity and gene expression in renal cell carcinoma.
Experimental Design:
Ten renal tumors were resected without renal hilar clamping from 10 patients with renal clear cell carcinoma. Immediately after tumor resection, a piece of tumor was snap frozen. Remaining tumor samples were stored at 4°C, 22°C, and 37°C and frozen at 5, 30, 60, 120, and 240 minutes. Histopathologic evaluation was conducted on all tissue samples, and only those with greater than 80% tumor were selected for further analysis. RNA integrity was confirmed by electropherograms and quantitated using RNA integrity number index. Altered gene expression was assessed by paired, two-sample t test between the zero time point and aliquots from various conditions obtained from the same tumor.
Results:
One hundred and forty microarrays were conducted. Some RNA degradation was observed 240 minutes after resection at 37°C. The expression of more than 4,000 genes was significantly altered by ischemia times or storage conditions. The greatest gene expression changes were observed with longer ischemia time and warmer tissue procurement conditions.
Conclusion:
RNA from kidney cancer remains intact for up to 4 hours post surgical resection regardless of storage conditions. Despite excellent RNA preservation, time after resection and procurement conditions significantly influence gene expression profiles. Meticulous attention to preacquisition variables is of paramount importance for accurate tumor profiling.
Insights
Ischemia and tissue handling significantly alter gene expression in kidney cancer, even with preserved RNA integrity. Careful attention to pre-acquisition variables is crucial for accurate renal cell carcinoma tumor profiling.
Area of Science:
- Oncology
- Molecular Biology
- Genomics
Background:
- Ischemia is known to alter gene expression in various tissues.
- Previous research has not specifically evaluated ischemia's effects on renal tumors.
- Understanding these effects is vital for accurate molecular profiling of kidney cancer.
Purpose of the Study:
- To investigate the impact of ischemia on RNA integrity and gene expression in renal cell carcinoma.
- To evaluate the influence of tissue procurement conditions on these molecular changes.
- To establish best practices for sample handling in renal tumor research.
Main Methods:
- Ten renal clear cell carcinoma tumors were resected without clamping.
- Tumor samples were snap-frozen immediately or stored at various temperatures (4°C, 22°C, 37°C) for up to 240 minutes.
- RNA integrity was assessed, and gene expression changes were analyzed using microarrays and statistical tests.
Main Results:
- RNA integrity was maintained for up to 4 hours post-resection, even at 37°C.
- Over 4,000 genes showed significant expression alterations due to ischemia time and storage conditions.
- Warmer temperatures and longer ischemia times resulted in the most substantial gene expression changes.
Conclusions:
- Kidney cancer RNA remains intact for several hours post-surgery, irrespective of storage conditions.
- Despite RNA stability, ischemia duration and procurement conditions significantly impact gene expression profiles.
- Precise pre-acquisition variable control is essential for reliable renal tumor profiling.
