Quantification of free RNA in serum and bronchial lavage: a new diagnostic tool in lung cancer detection?
Circulating cell-free nucleic acids have been detected in serum. In cancer patients levels of free DNA seem to be higher than in non-tumor controls and the detectable nucleic acids are partly of tumor origin. We asked whether free RNA can be detected as well in cell-free bronchial lavage fluid (BLF) supernatant, and whether quantification of free RNA allows to discriminate between tumor and non-tumor patients. 73 patients with lung cancer (NSCLC n=62, SCLC n=11) and 56 patients with non-malignant lung diseases were included. The RNA was isolated from 1 mL serum and lavage, respectively with the Quiamp MinElute Virus Vacuum Kit (Qiagen, Germany). A real-time quantitative RT-PCR assay was used for transcript quantification of the glyceraldehyde 3-phosphate dehydrogenase (GAPDH) gene. Intact RNA was detectable in cell-free supernatants of BLF from 126/129 patients and was investigated in all 64 serum samples. RNA levels were higher in the cell-free supernatant of BLF than in serum. RNA concentration in the BLF from tumor patients was higher than in patients with a benign lung disease (p=0.009). In conclusion, quantification of intact RNA isolated from BLF supernatant and from serum might become a valuable tool for differentiation between tumor and non-tumor patients.
Schmidt
Bernd
B
Division of Pneumology, University Hospital Charité, Charité - Universitätsmedizin Berlin, Campus Charité-Mitte, Schumannstr. 20-21, D-10117 Berlin, Germany. b.schmidt@charite.de
Engel
Eileen
E
Carstensen
Tim
T
Weickmann
Sabine
S
John
Matthias
M
Witt
Christian
C
Fleischhacker
Michael
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood*; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis* / Q000235:genetics*; D018288:Carcinoma, Small Cell / Q000175:diagnosis* / Q000235:genetics*; D004273:DNA, Neoplasm; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D012313:RNA / Q000032:analysis / Q000097:blood*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity
D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D012313:RNA