[show abstract][hide abstract] ABSTRACT: p16 gene plays an important role in the cell cycle regulation and is considered an important tumor suppressor gene. Several mechanisms of gene inactivation have been described; in this study we have focused on p16 gene promoter methylation. In colorectal cancer p16 gene methylation is a frequent event.
326 patients with sporadic colorectal cancer were included. DNA was extracted from tumor tissue samples obtained during the surgical procedure. Promoter methylation was analyzed using bisulfite modification and was detected by quantitative methylation-specific PCR. Frequency of p16 methylation was analyzed and compared with other clinicopathological variables.
p16 gene methylation was detected in 24.8% of patients. Methylation was associated with differentiation grade and with tumor location: methylation was frequent in poorly differentiated tumors and had low frequency in distal colon. The p16 promoter methylation discriminated a subgroup of patients with better prognosis in poorly differentiated tumors.
p16 methylation was a frequent event in our population and was able to induce differences in the overall survival of patients with poorly differentiated tumors.
Revista espanola de enfermedades digestivas: organo oficial de la Sociedad Espanola de Patologia Digestiva 03/2012; 104(3):111-7. · 1.65 Impact Factor
[show abstract][hide abstract] ABSTRACT: Angiogenesis plays an important role in tumor progression. The vascular endothelial growth factor (VEGF) is an important regulator of angiogenesis. In the present study we evaluated single nucleotide polymorphisms (SNPs) -2578C > A, -1154G > A, and +936C > T in the VEGF gene, and their prognostic value for patients operated on for colorectal cancer (CRC).
VEGF polymorphisms have been analyzed in 177 patients who had undergone surgical resection at Hospital Clínico San Carlos. The analysis of these polymorphisms was performed with specific probes for each nucleotide in a multiplex reaction using real-time PCR.
We only found a statistically significant relationship for one of these three polymorphisms, +936C > T, with gender and tumor location; 10.7% of patients heterozygotes for this SNP had tumors located in proximal colon, 35.2% in distal segment and 54.1% in rectum (p = 0.03). Patients with the +936T/T genotype had 100% overall survival (OS).
Patients with a +936T/T genotype showed increased survival, therefore the +936C > T SNP could be a useful marker in the follow-up and clinical management of patients with colorectal cancer.
Revista espanola de enfermedades digestivas: organo oficial de la Sociedad Espanola de Patologia Digestiva 01/2010; 102(1):20-31. · 1.65 Impact Factor