Pilot study of the sensitivity and specificity of the DNA integrity assay for stool-based detection of colorectal cancer in Malaysian patients.
BACKGROUND
To assess the diagnostic potential of tumor-associated high molecular weight DNA in stool samples of 32 colorectal cancer (CRC) patients compared to 32 healthy Malaysian volunteers by means of polymerase chain reaction (PCR).


METHODS
Stool DNA was isolated and tumor-associated high molecular weight DNA (1.476 kb fragment including exons 6-9 of the p53 gene) was amplified using PCR and visualized on ethidium bromide-stained agarose gels.


RESULTS
Out of 32 CRC patients, 18 were positive for the presence of high molecular weight DNA as compared to none of the healthy individuals, resulting in an overall sensitivity of 56.3% with 100% specificity. Out of 32 patients, 23 had tumor on the left side and 9 on the right side, 16 and 2 being respectively positive. This showed that high molecular weight DNA was significantly (p=0.022) more detectable in patients with left side tumor (69.6% vs 22.2%). Out of 32 patients, 22 had tumors larger than 1.0 cm, 18 of these (81.8%) being positive for long DNA as compared to not a single patient with tumor size smaller than 1.0 cm (p<0.001).


CONCLUSIONS
We detected CRC-related high molecular weight p53 DNA in stool samples of CRC patients with an overall sensitivity of 56.3% with 100% specificity, with a strong tumor size dependence.
Advanced Medical and Dental Institute, Universiti Sains Malaysia, Hospital Seberang Jaya, Pulau Pinang, Malaysia.
Ashwaq Hamid
AH
Yehya
Narazah Mohd
NM
Yusoff
Imran A
IA
Khalid
Hakimah
H
Mahsin
Ruzzieatul Akma
RA
Razali
Fatimah
F
Azlina
Kamil Sheikh
KS
Mohammed
Syed A
SA
Ali
D000230:Adenocarcinoma / Q000175:diagnosis* / Q000235:genetics; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics*; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000235:genetics; D004273:DNA, Neoplasm / Q000032:analysis*; D005243:Feces / Q000737:chemistry*; D005260:Female; D005820:Genetic Testing / Q000379:methods*; D006801:Humans; D008296:Malaysia; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010865:Pilot Projects; D016133:Polymerase Chain Reaction; D011379:Prognosis; D012680:Sensitivity and Specificity
D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm