Microarray-based identification and RT-PCR test screening for epithelial-specific mRNAs in peripheral blood of patients with colon cancer.
BACKGROUND
The efficacy of screening for colorectal cancer using a simple blood-based assay for the detection of tumor cells disseminated in the circulation at an early stage of the disease is gaining positive feedback from several lines of research. This method seems able to reduce colorectal cancer mortality and may replace colonoscopy as the most effective means of detecting colonic lesions.


METHODS
In this work, we present a new microarray-based high-throughput screening method to identifying candidate marker mRNAs for the early detection of epithelial cells diluted in peripheral blood cells. This method includes 1. direct comparison of different samples of colonic mucosa and of blood cells to identify consistent epithelial-specific mRNAs from among 20,000 cDNA assayed by microarray slides; 2. identification of candidate marker mRNAs by data analysis, which allowed selection of only 10 putative differentially expressed genes; 3. Selection of some of the most suitable mRNAs (TMEM69, RANBP3 and PRSS22) that were assayed in blood samples from normal subjects and patients with colon cancer as possible markers for the presence of epithelial cells in the blood, using reverse transcription-polymerase chain reaction (RT-PCR).


RESULTS
Our present results seem to provide an indication, for the first time obtained by genome-scale screening, that a suitable and consistent colon epithelium mRNA marker may be difficult to identify.


CONCLUSIONS
The design of new approaches to identify such markers is warranted.
Solmi
Rossella
R
Department of Histology, Embryology and Applied Biology, University of Bologna, Via Belmeloro 8, I-40126 Bologna, Italy. solmi@alma.unibo.it
Ugolini
Giampaolo
G
Rosati
Giancarlo
G
Zanotti
Simone
S
Lauriola
Mattia
M
Montroni
Isacco
I
del Governatore
Marco
M
Caira
Antonello
A
Taffurelli
Mario
M
Santini
Donatella
D
Coppola
Domenico
D
Guidotti
Lia
L
Carinci
Paolo
P
Strippoli
Pierluigi
P
D000328:Adult; D000368:Aged; D001331:Automation; D003110:Colonic Neoplasms / Q000097:blood*; D004847:Epithelial Cells / Q000737:chemistry*; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods; D006801:Humans; D053554:Keratin-20; D007633:Keratins / Q000097:blood; D008297:Male; D008565:Membrane Proteins / Q000235:genetics; D008875:Middle Aged; D009360:Neoplastic Cells, Circulating / Q000737:chemistry*; D009687:Nuclear Proteins / Q000235:genetics; D029543:Nucleocytoplasmic Transport Proteins / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D012333:RNA, Messenger / Q000097:blood*; D012334:RNA, Neoplasm / Q000097:blood*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D012697:Serine Endopeptidases / Q000235:genetics
C507499:KRT20 protein, human; D053554:Keratin-20; D008565:Membrane Proteins; D009687:Nuclear Proteins; D029543:Nucleocytoplasmic Transport Proteins; C112820:RANBP3 protein, human; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D007633:Keratins; D012697:Serine Endopeptidases; C500893:PRSS22 protein, human