Designing a rapid screening tool to diagnose predispostion to breast cancer

Predisposition to breast cancer can be screened by studying the two breast cancer susceptibility genes BRCA1 and BRCA2. BRCA1 is the gene of the focus in the current research as this gene was already proposed to be constitutively active in maintaining the genetic stability of DNA. BRCA1 is a large protein with many functional domains that interacts with other proteins and regulates the DNA repair process. It is evidenced that BRCA1 protein is functional in all the cell cycle checkpoints ensuring controlled and regulated cell division.;Germline mutations in the BRCA1 gene lead to defective DNA damage repair, G2/M cell cycle checkpoint, abnormal centrosome duplication and impaired spindle checkpoint. Loss of function of BRCA1 gene at the checkpoints causes the replication and transfer of the damaged DNA to the daughter cells. Thus mutations in BRCA1 do not directly result in tumor formation, but instead cause genetic instability resulting high risk of malignant transformation. The majority of the BRCA1 mutations produce either truncated or large proteins due to the addition or deletion of the amino acids because of the mutation.;The expression of BRCA1 gene in the mutant MDA-MB-436 cell line was compared with that of the wild type MCF-7 cell line. Reverse Transcription-Polymerase Chain Reaction (RT-PCR) of BRCA1 transcript in both the cell lines showed a prominent difference indicating the addition of bases in the mutant cell line. Western blot analysis of the BRCA1 protein showed a corresponding decrease in the expression of the protein produced in MDA-MB-436.