TWIST1 promoter methylation in primary colorectal carcinoma.

TWIST1 gene, a transcription factor that belongs to the family of basic helix-loop-helix proteins, has been related to tumor progression and metastasis in different cancers. The aim of our study was to investigate TWIST1 promoter methylation in patients with primary colorectal carcinoma and determine its correlation with prognostic factors and disease outcome. Seventy-three patients with primary colorectal adenocarcinoma were studied. From each patient two tissue samples were collected: one sample of the tumor and one sample of normal colorectal tissue from an area located 15 cm away from the tumor. Samples of colorectal mucosa obtained from 30 individuals without malignant disease were also studied as a control group. All tissues were analyzed through methylation-specific PCR. TWIST1 hypermethylation was detected in colorectal specimens of 46 patients with cancer, but in none of the tissues from the nonmalignant control group (p < 0.001). In cancer patients, TWIST1 hypermethylation was found in 38 of 73 tumor samples as compared with 20 of 73 matched samples of non-cancerous colorectal tissue (P = 0.001). TWIST1 hypermethylation was not correlated with prognostic predictors for the disease outcome, patients' overall survival and disease-free survival rates. We concluded that TWIST1 hypermethylation is present in the colon and rectum of most patients with colorectal carcinoma, suggesting this molecular alteration may be involved in the process of colorectal carcinogenesis.