The APC gene is responsible for familial adenomatous polyposis and is considered to be a tumor suppressor gene associated with development of sporadic colorectal tumors.
Retinoblastoma (RB) and the familial adenomatous polyposis/colorectal cancer (FAP/CRC) complex provide well-characterised examples of multistage carcinogenesis and inheritance of a predisposition to cancer.
High-resolution banding studies indicated that the deletion in the patient with polyposis spans the region 5q21-q22, which includes APC, a gene involved in familial adenomatous polyposis and sporadic colon cancer.
We searched for germ-line mutations of the APC gene in 79 unrelated patients with familial adenomatous polyposis using a ribonuclease protection analysis coupled with polymerase chain reaction amplifications of genomic DNA.
Loss of expression of the DCC gene during progression of colorectal carcinomas in familial adenomatous polyposis and non-familial adenomatous polyposis patients.
Genetic changes of both p53 alleles associated with the conversion from colorectal adenoma to early carcinoma in familial adenomatous polyposis and non-familial adenomatous polyposis patients.
The result suggests that the number of colorectal polyps in FAP patients may be associated with a difference in the stability or biological function of the truncated APC protein.
The results reported here indicate that (1) familial adenomatous polyposis is caused by an extremely heterogeneous spectrum of point mutations; (2) all the mutations found in this study are chain terminating; and (3) DGGE represents a rapid and sensitive technique for the detection of mutations in the unusually large APC gene.
These data suggest that more than one gene on chromosome 5q21 may contribute to colorectal carcinogenesis and that mutations at the APC gene can cause both adenomatous polyposis coli and Gardner's syndrome.
The presence of CHRPE in patients with adenomatous polyps from families with cancer family syndrome suggests possible involvement of the APC gene locus in syndromes associated with less florid polyp formation than seen in APC.
Our results provide information helpful to an understanding of the APC gene and will also contribute to presymptomatic diagnosis of members in FAP families.
Our results provide information helpful to an understanding of the APC gene and will also contribute to presymptomatic diagnosis of members in FAP families.