乳腺癌组织染色体17p13的杂合性缺失分析

ANALYSIS OF LOSS OF HETEROZYGOSITY ON CHROMOSOME BAND 17p13 IN BREAST CARCINOMA

目的检测乳腺癌组织在染色体１７ｐ１３区各位点的杂合性缺失。用方法通过Ｓｏｕｔｈｅｒｎｂｌｏｔ分析ＶＮＴＲ探针ＹＮＺ２２的杂合性缺失。用ＰＣＲ扩增微卫星重复序列后，同位素标记、变性胶分离分析微卫星ｍａｒｋｅｒ的杂合性缺失。结果１１例乳腺癌组织中有３例在染色体１７ｐ１３．３区有杂合性缺失，占２７％。缺失的上限为紧邻端粒的Ｄ１７Ｓ１８６６位点，缺失至Ｄ１７Ｓ１８４０位点，缺失的下限尚待确定。位于染色体１７ｐ１３．１区的ＴＰ５３位点有１例变化产生新长度的微卫星重复序列，４例存在杂合性缺失，其中２例在１７ｐ１３．３区也有杂合性缺失。结论乳腺癌组织在染色体１７ｐ１３．３区有较高的杂合性缺失。预示该区可能存在有关的抑癌基因。１７ｐ１３．１区的ＴＰ５３位点也有变化。

Objective:Detection of loss of heterozygosity(LOH) on chromosome band 17p13 in breast carcinoma.Methods:LOH of the loci on 17p13 was analysed with Southern hybridization by using probe of variable number tandem repeats YNZ22, and with PCR of microsatellite markers, radioisotope labeling and separation on denaturing polyacrylamide gel.Results:3/11(27%) cases of breast carcinoma were showed LOH on chromosome band 17p13.3. Upper limit of LOH is located at D17S1866 near the telomere of short arm of chromosome 17,while low limit of LOH needs to be further determined. There are new length of microsatellite repeats at the TP53 locus on chromosome band 17p13.1 in one case of breast carcinoma, and LOH at same locus is showed in 4 of breast carcinomas while LOH also was detected on chromosome band 17p13.3 in 2 of them.Conclusion:High incidence of LOH on chromosome band 17p13.3 in breast carcinoma was identified. This implies that there is a tumor suppressor gene on this region. There are aberrations at TP53 locus on chromosome band 17p13.1,which indicate the p53 gene and its product have a role in breast carcinogenesis.