# Colorectal cancer DNA methylation patterns from patients in Manaus, Brazil

## TL;DR

This study examines DNA methylation patterns in colorectal cancer patients from Manaus, Brazil, focusing on four tumor suppressor genes.

## Contribution

The study provides new methylation data for DAPK, CDH1, CDKN2A, and TIMP2 in a specific Brazilian population.

## Key findings

- DAPK and TIMP2 showed high methylation rates in both tumor and margin tissues.
- CDH1 and CDKN2A had lower methylation rates compared to DAPK and TIMP2.
- Methylation patterns varied significantly between tumor and adjacent non-neoplastic tissues.

## Abstract

DNA methylation is commonly linked with the silencing of the gene expression for many tumor suppressor genes. As such, determining DNA methylation patterns should aid, in times to come, in the diagnosis and personal treatment for various types of cancers. Here, we analyzed the methylation pattern from five colorectal cancer patients from the Amazon state in Brazil for four tumor suppressor genes, viz.: DAPK, CDH1, CDKN2A, and TIMP2 by employing a polymerase chain reaction (PCR) specific to methylation. Efforts in the study of colorectal cancer are fundamental as it is the third most of highest incidence in the world.

Tumor biopsies were methylated in 1/5 (20 %), 2/5 (40 %), 4/5 (80 %), and 4/5 (80 %) for CDH1, CDKN2A, DAPK, and TIMP2 genes, respectively. The margin biopsies were methylated in 3/7 (43 %), 2/7 (28 %), 7/7 (100 %), and 6/7 (86 %) for CDH1, CDKN2A, DAPK, and TIMP2, respectively.

Our findings showed DAPK and TIMP2 to be methylated in most samples from both tumor tissues and adjacent non-neoplastic margins; thus presenting distinct methylation patterns. This emphasizes the importance of better understanding of the relation of these patterns with cancer in the context of different populations.