Collection And Reservation Of Familial Adenomatous Polyposis Pedigree In Yunnan Province And Analysis Of Its APC Gene

Objective:To rescue and preserve the genetic resources of familial adenomatous polyposis (FAP) by collecting FAP pedigrees in Yunnan Province,and to provide genetic samples for prevention, treatment and etiology research of FAP. Meanwhile, to analysis the APC gene that predispose the disease susceptibility in patients with FAP from Yunnan Province and explore the mutation features of disease gene FAP-related and initial establish suitable program of screening FAP pedigree in Yunnan Province.Methods:Screening FAP patients through investigating the cases of colorectal cancer patients in the past 10 years and collecting new FAP patients of the endoscopy room, out-patients and the relevant departments nearly 3 years from the First Affiliated Hospital of Kunming Medical College, Yunnan Province Cancer Hospital, Red River State Hospital and Dali State Hospita. Using patients contacted by phone and door follow-up as index patients, the pedigree and all lineal and collateral relatives were interviewed. Peripheral venous blood samples of individuals were collected from these families. Collecting tissue specimens (including tumors, normal tissues beside or outside tumors) and paraffin-embedded sections of operative patients. These specimens were preserved in the Yunnan Province of hereditary colorectal cancer tissure bank. The whole coding region of APC gene of the FAP family probands were screened for germline mutations by using polymerase chain reaction (PCR) and DNA direct sequencing, and Mutation Surveyor software analyze sequencing results. Reference the APC gene sequence on the NCBI website to determine the sites of mutation and according to the sites of mutation screening high-risk relatives of their family.Results:Total of 10 FAP pedigrees were collected, including a Bai pedigree,2 Yi pedigrees and 7 Han pedigrees. There are 96 blood specimens,4 tissue specimens and 7 paraffin-embedded sections.DNA of all family members are extracted in reserve. Among the 10 probands subjected to genetic analysis of the APC gene, mutation was detected in 1 han proband (10%), which is the C to A transversion resulting in a stop codon at codon 1196 within exon15(c.3587C＞A,S1196X).Subsequently, another 8 members in APC gene mutaition family,7 of them have this mutation. The remaining 9 FAP pedigrees without identified significant mutation of APC gene.Conclusions:Through the collection of FAP family in Yunnan Province, rescue and preserve valuable genetic resources of FAP pedigrees, in order to provid the genetic samples of requirements of modern molecular oncology for future treatment, prevention and etiology research of FAP, and improve the value of the Yunnan Province of hereditary colorectal cancer tissure bank. We first analyze the APC gene mutations of FAP pedigree in Yunnan Province and found nonsense mutation has not been reported that the APC gene exon 15 c.3587C＞A(S1196X) in China. Among patients with FAP in Yunnan Province, the incidence of APC gene mutations was significantly lower than other areas at home and abroad is reported. others pathogenesis may exist in FAP patients without APC gene mutation. Aiming at results of APC gene mutations with low, establish two sets of suitable program of screening FAP pedigree in Yunnan Province.