The FHIT and Caveolin-1 genes are considered to be the intermediate penetrator genes that are involved in the development of Breast cancer. The basic aims of this thesis were to study the role of FHIT and CAV-1 gene in the development and progression of Breast cancer. The main aims of the study are: Detection of genetic aberrations in different exons of FHIT gene in Breast cancer patients using PCR- SSCP technique. Confirmation of detected mutations by Automated DNA Sequencing. Detection of genetic aberrations in different exons of CAV-1 gene and in Breast cancer patients using PCR- SSCP technique. Confirmation of detected mutations by Automated DNA Sequencing. Methylation Analysis of different exons of FHIT gene in Breast cancer patients using Standard PCR based Methylation Assays. Methylation Analysis of different exons of CAV-1 gene in Breast cancer patients using Standard PCR based Methylation Assays. Restriction fragment length polymorphism of ATM IVS10-6T G in Breast cancerpatients. Mutational detection of CHEK2 1100delC and NBS1 657del5 by Allele Specific Polymerase Reaction.