MYC quantitation in cell-free plasma DNA by real-time PCR for gastric cancer diagnosis.
BACKGROUND
Detection of tumor-associated genetic alterations in plasma of cancer patients has recently been suggested to be an accurate method for detecting early or recurrent cancer.


METHODS
We performed quantitative real-time PCR for MYC and GAPDH in tissue and plasma samples of 57 patients with gastric cancer and in plasma of 79 cancer-free individuals. We also performed two-color MYC fluorescence in situ hybridization (FISH) in tissue from the 57 patients with gastric cancer.


RESULTS
The tissue MYC/GAPDH ratio by real-time PCR was significantly correlated with MYC status by FISH (p<0.001). The mean ratio of plasma MYC/GAPDH was 5.226+/-3.578 (range: 1.25-18.35) in gastric cancer patients, and 2.436+/-0.881 (range: 1.00-5.00) in the healthy volunteers (p<0.001). We used receiver-operating characteristics (ROC) curve analysis to select two optimal plasma MYC/GAPDH cut-offs of 2.725 and 5.225. The sensitivity and specificity were 75.4% and 76.9% at 2.725, 38.6% and 100% at 5.225, respectively. The plasma MYC/GAPDH ratio from cancer patients was significantly correlated with the tissue MYC/GAPDH ratio (p=0.009), and tissue MYC status by FISH (p=0.024).


CONCLUSIONS
These findings suggest that the plasma MYC/GAPDH ratio, as determined by real-time PCR, may be an alternative non-invasive approach for detecting gastric cancer.
Park
Kyoung Un
KU
Department of Laboratory Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
Lee
Hee Eun
HE
Park
Do Joong
DJ
Jung
Eun Ji
EJ
Song
Junghan
J
Kim
Hyung-Ho
HH
Choe
Gheeyoung
G
Kim
Woo Ho
WH
Lee
Hye Seung
HS
D014408:Biomarkers, Tumor / Q000097:blood*; D002466:Cell Nucleolus / Q000235:genetics; D002503:Centromere / Q000235:genetics; D004247:DNA / Q000097:blood* / Q000235:genetics; D005260:Female; D005784:Gene Amplification; D016259:Genes, myc / Q000235:genetics*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000097:blood / Q000235:genetics; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008875:Middle Aged; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology
D014408:Biomarkers, Tumor; D004247:DNA; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases