The frequency of the point mutation ( polymorphism) in brca 1 and brca 2, common in breast cancer

ABSTRACT Introduction: Breast cancer, the most frequent malign tumor in the world, constitutes approximately 25% of all women cancers. Although it can be seen in all age groups, breast cancer, except familial cases rarely seen at an early age. BRCA 1,2 mutations are held responsible for the most of breast cancers, develop due to point mutations and 3% of overall breast cancers. Hundreds of different mutations are reported in BRCA 1 and BRCA 2 genes spreading throughout the decoding zones.In our research, we aim to designate the frequency of polymorphic point mutations belonging to BRCA 1 (rs16942, rs1799966) and BRCA 2 (rs144848, rs1799944) genes in our region , ascertained frequently, in order to identify genetic susceptibility in breast cancer by using the "LightCycler" PRC device with the method of Hibridization Prob from the group of PRC specific identification and determine the relationship of those mutation rates with ER positive, the state of HER 2 , stage, grade and age. Materials and Method: In our research 96 patients, diagnosed breast cancer among the young women group (under the age of 44) are taken to the study in Diyarbakır Dicle University, Faculty of Medicine -Departman of Oncology. Genomic DNA isolation from the the paraffin-embedded tumor tissues is done and DNA purity and concentarion is held. Then polymorphism mutations in BRCA 1 and BRCA 2 genes from those test tubes are defined with Real -Time PRC. Four points mutation , the most frequent one which is confirmed in researches in our country is evaluated in our research. Some parameters are assigned as age, grade, ER, the state of HER 2 and stage belongig to those patients. Statistical evaluation of the reseach is practiced by using SPSS 21.0 computer programme. p≤0.05 is accepted meaningful statistically. Results: According to the data aquired from our study we found out 14(14,5%) homozygotes (GG), 55(57,3%) heterozygotes(AG) in rs16942; 18(18,75%) homozygotes(GG), 46(47,9%)heterozygotes (AG) in rs1799966 belong to BRCA1 gene; 9(9,37%) homozygotes (TT), 25(26,04%) heterozygotes (GT) in rs144848; 2(2,08%) homozygotes (GG), 3(3,12%) heterozygotes (AG) in rs1799944 belong to BRCA 2 gene, point muations among the patients out of 96 cases. These v rates are higher than the study rates made in other regions in our country. It is found out that when comparing point mutations and Grade relation, aproximate p value is 0.464 , when comparing point mutations and ER positiveness aproximate p value is 0.647 and when comparing point mutations and HER 2 positiveness p value is 0.358. Conclusion: In our region the rate of polymorphism mutations in BRCA 1-2 is seen in high-frequency. For this reason it is essential to make a genetic screening to the early aged-cancerous patients and their family members. Key Words: BRCA-1 BRCA-2; breast cancer; point mutation, polymorphism, LightCycler PCR.