[Clinical analysis and molecular genetic study of hereditary nonpolyposis colorectal cancer kindreds].
OBJECTIVE
To study the clinicopathological and molecular genetic characteristics of hereditary nonpolyposis colorectal cancer (HNPCC), to enable the early diagnosis and to evaluate the treatment.


METHODS
We analyzed 12 families of HNPCC from Wenzhou, Zhejiang province, China. Mismatch repair genes hMSH2 and hMLH1 expression and microsatellite instability of tumor tissue were studied using microdissection, microsatellite analysis, immunohistochemical staining and Gene Scan analysis. Direct DNA sequencing of hMSH2 and hMLH1 were performed subsequently.


RESULTS
Altogether 32 patients with colorectal cancer were recognized in 12 HNPCC families, with the median age of 45.2 years (75.0% before the age of 50 years). The proximal tumors accounted for 51.1%, while multiple colorectal cancers accounted for 34.4%. Poor differentiation cancers occupied half of the patients (53.1%). And 68.8% of the patients had the tumor of Dukes A and B. Among 12 HNPCC families, 7 cases in 6 HNPCC families developed extracolonic cancer. 13 cases died during follow up of 1 - 23 years. The median survival time was 6.4 years. 19 alive cases followed up from 1 to 28 years. All tumors (9/9) displayed microsatellite instability, with the half losing hMSH2 or hMLH1 expression. In the 5 genetic analyzed kindreds 3 possessed germline mutation. Two of three mutations have not been reported in the worldwide database previously.


CONCLUSIONS
HNPCC showed distinct clinicopathological characteristics. Microsatellite instability analysis and immunohistochemical staining might be the effective screening methods before direct DNA sequencing for the detection of mutation in mismatch repair genes. It is important to analyze the members of affected families.
Luo
Ding-cun
DC
Department of Surgical Oncology, Second Peoples' Hospital of Wenzhou, Wenzhou 325028, China.
Cai
Qi
Q
Sun
Meng-hong
MH
Ni
Yao-zhong
YZ
Tao
Chong-wei
CW
Chen
Zhe-jing
ZJ
Shi
Da-ren
DR
D048868:Adaptor Proteins, Signal Transducing; D000328:Adult; D000368:Aged; D002352:Carrier Proteins; D002681:China; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm / Q000737:chemistry / Q000235:genetics; D004268:DNA-Binding Proteins / Q000032:analysis / Q000235:genetics*; D005192:Family Health; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein; D009154:Mutation; D009363:Neoplasm Proteins / Q000032:analysis / Q000235:genetics*; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000235:genetics*
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D004273:DNA, Neoplasm; D004268:DNA-Binding Proteins; C501486:MLH1 protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; C497172:MSH2 protein, human; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein