Screening for differentially methylated genes among human colorectal cancer tissues and normal mucosa by microarray chip.

UNLABELLED: High density DNA methylation microarrays were used to study the differences of gene methylation level in six pairs of colorectal cancer (CRC) and adjacent normal mucosa. We analyzed the profile of methylated genes by NimbleGen Microarray and the biologic functions by NIH-NAVID. In addition, preliminary validation studies were done in six pairs of samples by MSP (methylation-specific PCR). A total of 4,644 genes had a difference in methylation levels. Among them 2,296 were hypermethylated (log2ratio > 1), 2,348 genes were hypomethylated (log2ratio < -1), in which 293 hypermethylated and 313 hypomethylated genes were unmapped according to the NIH-NAVID. All these genes were randomly distributed on all the chromosomes. However, chromosome 1 contained the most of the hypermethylated genes (232 genes), followed by chromosome 19 (149 genes), chromosome 11 (144 genes), chromosome 2 (141 genes), chromosomes 3 (127 genes). Through the analysis of the statistics, There were 2 hypermethylated/3 hypomethylated genes involved in six pairs of samples simultaneously, followed by 10/14 in five samples, 34/37 in four samples, 101/113 in three samples, 341/377 in two samples, 1,808/1,804 in one sample. According to gene ontology analysis, some physiological processes play important roles in the cell division and the development of tumor, such as apoptosis, DNA repair, immune, cell cycle, cell cycle checkpoint, cell adhesion and invasion etc. Through Preliminary validation, there were two genes (St3gal6, Opcml) in thirty top-ranking genes shown hypermethylated in six pairs of CRC and adjacent normal mucosa. CONCLUSIONS: High density DNA methylation microarrays is an effective method for screening aberrantly methylated genes in CRC. The methylated genes should be further studied for diagnostic or prognostic markers for CRC.

[Regression analysis of the characteristics and outcome of colorectal cancer 1995 - 2007].

OBJECTIVE: To explore the clinical characteristics and the prognostic factors of patients with colorectal cancer. METHODS: The data of 2042 cases of colorectal cancer, pathologically confirmed at our hospital from January 1995 to December 2007, were summarized and analyzed. RESULTS: The median age of all cases with colorectal cancer was 59 years old. The high-risk age ranged from 50 to 70 years old. The ratio of male and female was 1.4:1. The lesions located in rectum accounted for 46.2% and those for 22.0% in sigmoid. Patients under age 40 had a higher percentage of poor differentiation (33.5%) and mucinous carcinoma (16.7%). The cases with confirmed stage I, II, III and IV were 5.8%, 42.9%, 31.0% and 20.3% respectively. For all cases, the 1-, 3-, 5- and 10-year survival rates were 92.3%, 73.9%, 65.1% and 57.5% respectively. The independent risk factors for patient prognosis were age, gross type, differentiation, TNM staging and surgical type. Adjuvant chemotherapy was a protective factor. As compared with phase I (1995 - 2001), phase II (2002 - 2007) had a higher proportions of employing stapler, Dixon operation and adjuvant chemotherapy. The 1-, 3- and 5-year survival rates of phase II were higher than phase I (93.4%, 78.0% and 73.2% vs 90.6%, 69.2% and 58.8%). CONCLUSION: The prognostic factors of patients with colorectal cancer are age, gross type, differentiation, TNM staging, surgical type and adjuvant chemotherapy.

Effects of diabetes mellitus on prognosis of the patients with colorectal cancer undergoing resection: a cohort study with 945 patients.

BACKGROUND: Diabetes mellitus plays an important role in cancer prevalence and outcomes. The aim of this study was to evaluate the influence of DM on stages and outcomes among patients with colorectal cancer. METHODS: The study enrolled 945 patients who were diagnosed as having colorectal carcinoma from August 1994 to December 2002. In the cohort, 26 patients were diagnosed as having DM. With a median follow-up of 45.8 months, differences in overall survival and disease-free survival between the diabetes and non-diabetes groups were analyzed. RESULTS: Kaplan and Meier analysis showed that there were no significant differences between the two groups in overall survival rates at 3 years or 5 years. At 5 years, patients with DM, compared with patients without diabetes, experienced a significantly lower disease-free survival rate (34.2% diabetics vs. 55.1% non-diabetics; P = 0.025). CONCLUSIONS: DM was associated with an increased risk of recurrence in patients with colorectal cancer.