British researchers have discovered a process to successfully obtain and store high quality RNA from lung tumor biopsies. The discovery of this novel method of tissue banking lung cancer diagnostic specimens could be used to improve personalized medicine for lung cancer patients. The findings were published in the Journal of Thoracic Oncology.
Analyzing the genes expressed by cancer cells allows for a better understanding of a patient’s specific disease and in turn, a more personalized approach to treatment. But obtaining RNA from a tumor in the lungs in order to conduct the genetic analysis is a challenge. Currently, lung cancer researchers are limited to using RNA extracted from early-stage tumors removed during surgery. The small quantities of tissue extracted during routine diagnostic biopsies have not been useful to researchers due to their small size and the variety of ways they have been processed.
For this study, the researchers received consent from patients to take extra biopsies for research purposes during the diagnostic procedure. Biopsies were obtained using the three most frequently used techniques: endobronchial biopsy forceps, transbronchial needle aspirate, or CT-guided needle biopsy. Acceptable RNA for gene expression analysis was extracted from 72% of lung cancer biopsies.
The researchers immediately froze some of the biopsies in liquid nitrogen, while the others were first treated with a RNA preservative (RNAlater) before freezing. Use of the RNA preservative resulted in higher quality, more intact RNA from biopsies taken via all methods.
Storage in the RNA preservative doubled the number of biopsies that met the minimum yield quality criteria for analysis compared with immediate freezing—10 of 16 biopsies versus 5 of 16. Using the RNA preservative, 70% of biopsies taken by needle aspiration were suitable for analysis compared with 40% frozen, and 50% of the RNA preservative endobronchial biopsies were acceptable compared with 17% of the frozen ones. A full 100% of the CT-guided needle biopsies met the criteria when treated with RNA preservative.