Puviarasan Gopal1, Zeeshan Ahmed1, Vishnubhotla Venkata Ravi Kant2, G V Rao1, Pradeep Rebala1

1Department of Surgical Gastroenterology, Asian Institute of Gastroenterology, Hyderabad, India
2Department of Research, Asian Institute of Gastroenterology, Hyderabad, India.


Objective: Methylation status of Septin9 (SEPT9) and vimentin (VIM) genes in circulating tumor DNA of colorectal cancer (CRC) patients is a promising bio-marker for the early detection of CRC. The aim of the present study was to identify the methylation status in promoter regions of the SEPT9 and VIM genes in a cohort of Indian patients with biopsy proven colorectal cancer.

Material and Methods: Forty-five consecutive patients of colorectal cancer were recruited. 10 mL venous samples were collected from each patient and processed for isolation of cell-free DNA, bisulfite conversion of cell-free DNA, polymerase chain reaction (PCR) amplification and detection of SEPT9 and VIM genes.

Results: Partial methylation in vimentin was present in 42.22% of the patients and 57.78% showed no methylation and none of the tumors had complete methylation. Only three (6.66%) patients showed complete methylation patterns in SEPT9 and the remaining 42 (93.33%) tumors showed partial methylation. Considering the two genes together, only three (6.66%) out of 45 showed complete methylation. The association of methylation patterns in both genes (complete, partial, and no methylation) with sex, age, T stage, N stage, M stage, CEA, histology, and location (right or left colon) were explored and none of these parameters were statistically significant.

Conclusion: In our study, only 6.66% CRC patients showed hypermethylation and there was no association of methylation patterns in the both genes (complete, partial, and no methylation) with any of the parameters like age, sex, TNM stage, CEA, and histology.

Keywords: Colorectal neoplasms, cell-free nucleic acids, methylation

Cite this article as: Gopal P, Ahmed Z, Ravi Kanth VV., Rao GV, Rebala P. Circulating tumor DNA for monitoring colorectal cancer: A prospective observational study to assess the presence of methylated SEPT9 and VIM promoter genes and its role as a biomarker in colorectal cancer management. Turk J Surg 2023; 39 (2): 107-114.


Ethics Committee Approval

This study was approved by Asian Institute of Gastroenterology Ethics Committee (Study-Approval Number: AIG/ IEC32/10.2018-09, Date: 06.11.2018).

Peer Review

Externally peer-reviewed.

Author Contributions

Concept - PG, ZA, PR; Design - PG, PR; Supervision - PR, GVR; Data Collection and/or Processing - PG, ZA; Analysis and/or Interpretation - PG, ZA, GVR; Literature Search - ZA, GVR; Writing Manuscript - ZA; Critical Reviews - PR, GVR, PG, ZA.

Conflict of Interest

The authors have no conflicts of interest to declare.

Financial Disclosure

The authors declared that this study has received no financial support.