The APC gene on chromosome 5 causing adenomatous polyposis coli represents a minority of the inherited colon cancer cases, while hereditary-non polyposis colon cancer (HNPCC) may cause five percent of all human colon cancer.
We report novel APC mutations and present two FAP cases that suggest familial aggregation of thyroid cancer and demonstrate the need to consider attenuated FAP also among elderly patients with colon cancer.
Our findings suggest APC mutations alter regulation of both beta- and gamma-catenin, perhaps explaining why the frequency of APC mutations in colon cancer far exceeds that of beta-catenin mutations.
In order to assess whether chronic infection with T. muris does indeed influence the development of cancer hallmarks, both wild type mice and colon cancer model (APC min/+) mice were infected with this parasite.
We further showed that the colon cancer cell line expressing the wild-type APC gene was more sensitive to a DNA-methylating agent due to decreased DNA repair by long patch BER than the cell line expressing the mutant APC gene lacking the proliferating cell nuclear antigen-interacting protein-like box.
Three APC isoforms that differ in their amino-terminal domains were evaluated by gene transfer experiments using a colon cancer cell line that lacks functional APC.
One dose of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) or 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) induces tumours in Min/+ mice by truncation mutations or LOH in the Apc gene.
These results suggest that ZnCl2 inhibits the proliferation of colon cancer cells (which carry the wild-type APC gene) through stabilization of the APC protein and cell cycle arrest in the G2/M phase.
Secretory clusterin (sCLU) is a stress-induced, pro-survival glycoprotein elevated in early-stage cancers, in particular in APC/Min-defective colon cancers. sCLU is upregulated after exposure to various cytotoxic agents, including ionizing radiation (IR), leading to a survival advantage.
Germline mutations of APC in patients with Turcot syndrome (colon cancer and medulloblastoma), was well as somatic mutations of APC, beta-catenin, and Axin in sporadic medulloblastomas (MBs) have shown the importance of WNT signaling in the pathogenesis of MB.
A subset of cases is associated with colon cancer and APC germline mutations (Turcot syndrome), and APC and beta-catenin point mutations occur in up to 10% of sporadic cases, indicating the involvement of the Wnt pathway in the development of medulloblastoma.
The apparently low incidence of colon cancer in the African population may be ascribed either to the rare occurrence of the 'second hit' needed for polyp formation or to a lower incidence of mutations in the APC gene.
Neonatal exposure to the food mutagen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine via breast milk or directly induces intestinal tumors in multiple intestinal neoplasia mice.
Somatic mutations of the APC gene have also been identified in the majority of sporadic colorectal carcinomas, and mutation of the APC gene appears to be an early step in the initiation of colon cancer.
APC mutations were associated with poor prognosis in (5-fluorouracil treated) stage III colon cancers (p = 0.005; HR = 4.1), an effect that was further enhanced by mutations in MAPK pathway (KRAS, NRAS, BRAF) genes.
It is important to evaluate the effects of proposed interventions to reduce the risk of disease among carriers of a highly penetrant mutation, such as the mutations in BRCA1 and BRCA2 for breast and ovarian cancers or in APC and MLH1 or MSH2 for colon cancer.
Mutations in the adenomatous polyposis coli gene (which encodes a protein called APC) are associated with the formation of intestinal polyps and colon cancers.
Truncating mutations of the APC gene result in the constitutive stabilisation of β-catenin and the initiation of colon cancer, although tumour cells tolerate the expression of wild-type APCL.