11059 Background: Since the pathologic stage is the most powerful prognostic factor for colorectal cancer (CRC), there is a strong need of non-invasive methods for early detection. Cell-free circulating DNA (cfDNA) released from cancer cells varies in size. It has been suggested that cfDNA (ALU repeats of 115 bp, representative of total DNA; ALU repeats of 247 DNA, representative of tumor DNA) may be associated with presence of tumor. Aim of this study was then to investigate whether the cfDNA may have a role as marker of CRC detection and progression. Methods: cfDNA was extracted from plasma samples from 136 patients with primary CRC at different stages [median age 64 yrs; male/female 78/58; stages I-II, 61; stages III-IV, 75], and from 24 patients with adenomas [median age 67 yrs; male/female 17/7)] and from 55 clean-colon healthy subjects [median age 56 yrs; male/female 13/43). cfDNA was assessed by quantitative real-time PCR (qPCR) of ALU repeats with 2 sets of primers (115 and 247 bp) amplifying different lengths of DNA. The levels of cfDNA (ALU-115, ALU-247) of CRC patients (stages I-II and stages III-IV) were compared with those of healthy subjects and patients with adenoma. Results: The median concentrations of total cfDNA (ALU115) in the plasma samples from patients with stages III-IV and stages I-II CRC, adenoma and normal controls were 52,4, 11.9; 1.9, and 1.7 ng/ml, respectively (p<.0001). The corresponding figures for tumor-related cfDNA (ALU247) were 48.8, 4.7, 2.2, and 0.7 ng/ml, respectively. (p<.0001). With a cut-off of 4.86 ng/ml, total DNA (ALU115) showed a sensitivity of 78.52 (95% CI 70.6–85.1) and a specificity of 86.08 (95% CI 76.4–92.8) in distinguishing patients with CRC from non-CRC [AUC: 0.860 (95% CI 0.81–0,90), p-value=.0001]. With a cut-off of 3.04, cfDNA tumor-related (ALU247) showed a sensitivity of 77.94 (95% CI 70.0–84.6) and a specificity of 82.28 (95% CI 72.1–90.0) in distinguishing patients with CRC from non-CRC [AUC: 0.864 (95% CI 0.81–0,91), p-value=.0001]. Conclusions: Both ALU115 and ALU 247 fragments of circulating cfDNA seem promising non-invasive molecular markers of detection and progression of CRC. The findings of the current study require to be confirmed on larger cohorts of patients with CRC and colonic adenoma. No significant financial relationships to disclose.
Evaluation of Plasma Cell‐Free Circulating DNA Integrity in Patients with Prostate Cancer in Jamaica
