The GATA family of transcription factors consists of six proteins (GATA1-6) which are involved in a variety of physiological and pathological processes. GATA1/2/3 are required for differentiation of mesoderm and ectoderm-derived tissues, including the haematopoietic and central nervous system. GATA4/5/6 are implicated in development and differentiation of endoderm- and mesoderm-derived tissues such as induction of differentiation of embryonic stem cells, cardiovascular embryogenesis and guidance of epithelial cell differentiation in the adult.

NDRG4 is a candidate tumor suppressor gene in colorectal cancer whose expression is frequently inactivated by promoter methylation. NDRG4 promoter methylation is a potential biomarker for the noninvasive detection of colorectal cancer in stool samples.

Purpose: The transcription factors GATA4 and GATA5 are involved in gastrointestinal development and are inactivated by promoter hypermethylation in colorectal cancer. Here, we evaluated GATA4/5 promoter methylation as potential biomarkers for noninvasive colorectal cancer detection, and investigated the role of GATA4/5 in colorectal cancer. Experimental Design: Promoter methylation of GATA4/5 was analyzed in colorectal tissue and fecal DNA from colorectal cancer patients and healthy controls using methylation-specific PCR. The potential function of GATA4/5 as tumor suppressors was studied by inducing GATA4/5 overexpression in human colorectal cancer cell lines. Results: GATA4/5 methylation was observed in 70% (63/90) and 79% (61/77) of colorectal carcinomas, respectively, and was independent of clinicopathologic features. Methylation frequencies in normal colon tissues from noncancerous controls were 6% (5 of 88, GATA4; P < 0.001) and 13% (13 of 100, GATA5; P < 0.001). GATA4/5 overexpression suppressed colony formation (P < 0.005), proliferation (P < 0.001), migration (P < 0.05), invasion (P < 0.05), and anchorage-independent growth (P < 0.0001) of colorectal cancer cells. Examination of GATA4 methylation in fecal DNA from two independent series of colorectal cancer patients and controls yielded a sensitivity of 71% [95% confidence interval (95% CI), 55-88%] and specificity of 84% (95% CI, 74^95%) for colorectal cancer detection in the training set, and a sensitivity of 51% (95% CI, 37^65%) and specificity of 93% (95% CI, 84-100%) in the validation set. Conclusions: Methylation of GATA4/5 is a common and specific event in colorectal carcinomas, and GATA4/5 exhibit tumor suppressive effects in colorectal cancer cells in vitro. GATA4 methylation in fecal DNA may be of interest for colorectal cancer detection.

Case -cohort analyses were performed on meat and fish consumption in relation to K-ras mutations in 448 colon and 160 rectal cancers that occurred during 7.3 years of follow-up, excluding the first 2.3 years, and 2948 subcohort members of The Netherlands Cohort Study on diet and cancer. Adjusted incidence rate ratios and 95% confidence intervals were computed for colon and rectal cancer and for K-ras mutation status subgroups. Total fresh meat, most types of fresh meat and fish were not associated with colon or rectal cancer, neither overall nor with K-ras mutation status. However, several weak associations were observed for tumours with a wild-type K-ras, including beef and colon tumours, and an inverse association for pork with colon and rectal tumours; for meat products, an increased association was observed with wild-type K-ras tumours in the colon and possibly with G4A transitions in rectal tumours.

The adenomatous polyposis coli (APC) gene is considered to be a gatekeeper in colorectal tumourigenesis. Inactivating mutations in APC have been reported in 34-70% of sporadic colorectal cancer patients, the majority of which occur in the mutation cluster region (MCR). In this study, tumour tissue from 665 incident colorectal cancer patients, who originate from 120 852 men and women (55-69 years of age at baseline) participating in The Netherlands Cohort Study, was evaluated for the occurrence and type of APC mutations with regard to age at diagnosis, gender, family history of colorectal cancer, Dukes' stage, tumour differentiation and sub-localization. Mutation analysis of the MCR, which spans codons 1286-1513, was performed on archival adenocarcinoma samples using macrodissection, nested PCR and direct sequencing of purified PCR fragments. A large number of genetic aberrations (n = 978), including point mutations (n = 833), deletions (n = 126) and insertions (n = 19) was detected in the MCR in 72% of patients (479/665). In particular, we observed a large number of missense mutations, more than reported previously. This may indicate involvement in colorectal carcinogenesis, although their significance for APC functions is unclear. Truncating mutations were found in 37% of patients (248/665). Patients with rectosigmoid and rectum tumours relatively more frequently harboured C > T nonsense mutations and truncating frameshift mutations as compared with patients with proximal and distal colon tumours (P = 0.009 and P = 0.045, respectively). Differences in occurrence of truncating mutations with regard to tumour sub-localization suggest a different aetiology of tumourigenesis in colon and rectum.