ABSTRACT
PURPOSE: The regulator of angiogenesis most extensively studied is VEGF. VEGF mRNA in plasma from patients with colorectal cancer was analyzed as a possible surrogate marker of tumor angiogenesis. METHODS: VEGF mRNA was measured by quantitative PCR in plasma, tumors and circulating tumor cells from colorectal cancer patients. Circulating VEGF protein was analyzed by ELISA. Microvessel density was determined. RESULTS: Levels of VEGF mRNA and protein in plasma were higher in patients than in controls. VEGF mRNA was overexpressed in tumors with respect to normal tissues. Levels of VEGF protein were associated with VEGF mRNA in plasma, but no associations with tumor samples were found. A trend to statistical significance was shown between high VEGF mRNA and vascular invasion. MVD was not related to VEGF mRNA in plasma. CONCLUSIONS: Thus, VEGF mRNA could be a marker similar to VEGF protein in plasma.
Subject(s)
Colorectal Neoplasms/genetics , Colorectal Neoplasms/pathology , Neovascularization, Pathologic/genetics , RNA, Messenger/genetics , Vascular Endothelial Growth Factor A/genetics , Colorectal Neoplasms/surgery , DNA Primers , Genetic Markers , Humans , Neovascularization, Pathologic/pathology , Polymerase Chain Reaction , RNA, Neoplasm/blood , RNA, Neoplasm/genetics , RNA, Neoplasm/isolation & purificationABSTRACT
The INK4a/ARF locus encodes two unrelated tumor suppressor proteins, p16INK4a and p14ARF, which participate in the two main cell-cycle control pathways, p16-Rb and p14-p53. Methylation of CpG promoter islands has been described as a mechanism of gene silencing. Exon 1 of the p16INK4a gene and the p14ARF promoter gene reside within CpG islands. Therefore, both can become methylated de novo and silenced. It has recently been proposed that the methylation changes in certain genes could be used as molecular markers for the detection of almost all forms of human cancer. Here, we analyzed concomitantly in each tumor sample and normal tissue the methylation status of p16INK4a and p14ARF by methylation-specific PCR (MSP) in 100 breast, 95 colon and 27 bladder carcinomas. A series of clinicopathological parameter were obtained from the medical records of the patients, p14ARF showed a higher rate of hypermethylation than p16INK4a in all three tumor types. p16INK4a and p14ARF aberrant methylation was significantly correlated with poor prognosis clinicopathological parameters of the three tumor types. We conclude that both p16INKa and p14ARF hypermethylation may be involved in breast, colon and bladder carcinogenesis, with special emphasis on the role of the lesser studied p14ARF gene, and that tumors with aberrant methylation in the two genes were associated with worse prognosis.
Subject(s)
Cyclin-Dependent Kinase Inhibitor p16/genetics , DNA Methylation , Neoplasms/genetics , Tumor Suppressor Protein p14ARF/genetics , Breast Neoplasms/genetics , Carcinoma/genetics , Colonic Neoplasms/genetics , Female , Humans , Male , Middle Aged , Prognosis , Promoter Regions, Genetic , Urinary Bladder Neoplasms/geneticsABSTRACT
PURPOSE: We examine prospectively whether the presence of plasma DNA with tumor characteristics before mastectomy is a predictive factor related to recurrence and disease-free survival (DFS). EXPERIMENTAL DESIGN: A series of 147 patients with breast carcinomas, selected sequentially, was analyzed. The characterization of plasma DNA, based on similar alterations in tumor and plasma DNA, was achieved with six polymorphic markers (D17S855, D17S654, D16S421, TH(2), D10S197, and D9S161) and mutations in the TP53 gene. Recurrence, DFS, overall survival, and 12 other clinicopathological parameters were obtained. Univariate and Cox's multivariate studies were performed. RESULTS: A total of 142 patients were eligible for study. A total of 104 tumors (73.2%) showed at least one molecular alteration. In 61 patients (42.9%), a similar molecular alteration was detected in plasma DNA and tumor DNA. No alterations were found in the plasma DNA of the remaining 81 patients (57%). During the follow-up period (median, 22 months; range, 1-46 months), we observed 23 recurrences (16%), the distribution of which was significantly different (P = 0.005) with regard to plasma DNA [17 patients (74%) with circulating tumor DNA and 6 patients (26%) without tumor plasma DNA]. Univariate statistical analysis confirmed the prognostic significance of the already known parameters (tumor size, lymph node metastases, and stage) and demonstrated that tumor plasma DNA was a predictor of DFS. In multivariate analysis, an independent borderline significance was observed for tumor plasma DNA. CONCLUSIONS: Tumor DNA in plasma at diagnosis in breast cancer patients can predict DFS, and its determination could be used as a prognostic factor in these patients.
