Choosing appropriate molecular markers is an intriguing area of oncology research to find out individualized treatments. Targeted therapy, which consists of therapeutic agents directed at specific molecules, is contemporary approach against cancers. This book looks at the impact of immune-editing on the aetiology of breast cancer to determine if this would provide novel prognostic markers for patients'' management. The expression of membrane CRPs (mCRP) CD59, CD55, CD46, also HLA class-I was measured on an extensive series of breast cancer tissues, using tissue microarrays. Tissue microarrays linked to good clinicopathological databases with a long term follow up are useful tools to determine new prognostic indicators that can be used in future clinical management. Both CD59 and HLA class-I were identified to be independent markers of prognosis. They could be used in addition to Nottingham Prognostic Index to help further stratify patients for adjuvant therapy. Patients lacking CD59 but expressing HLA could be candidates for aggressive chemotherapy as they have a poor predicted outcome.