title: A Review of the Clinical Implications of Breast Cancer Biology.
abstract: BACKGROUND
  Histologically similar tumors may have different prognoses and responses to treatment. These differences are due to molecular differences. Hence, in this review, the biological interaction of breast cancer in several different areas is discussed. In addition, the performance and clinical application of the most widely-recognized biomarkers, metastasis, and recurrences from a biological perspective and current global advances in these areas are addressed.
  
  
  OBJECTIVE
  This review provides the performance and clinical application of the most widely-recognized biomarkers, metastasis, and recurrences from the biological perspective and current global advances in these areas.
  
  
  METHODS
  PubMed, Scopus, and Google Scholar were searched comprehensively with combinations of the following keywords: "breast cancer," "biological markers," and "clinical." The definition of breast cancer, diagnostic methods, biological markers, and available treatment approaches were extracted from the literature.
  
  
  RESULTS
  Estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor-2 (HER-2), and Ki-67 are the most well-known biological markers that have important roles in prognosis and response to therapeutic methods. Some studies showed the response of ER-positive and PR-negative tumors to anti-estrogenic treatment to be lower than ER-positive and PR-positive tumors. Patients with high expression of HER-2 and Ki-67 had a poor prognosis. In addition, recent investigations indicated the roles of new biomarkers, such as VEGF, IGF, P53 and P21, which are associated with many factors, such as age, race, and histological features.
  
  
  CONCLUSIONS
  The objective of scientists, from establishing a relationship between cancer biology infrastructures with clinical manifestations, is to find new ways of prevention and progression inhibition and then possible introduction of less dangerous and better treatments to resolve this dilemma of human society.
authors.affiliation: Young Researchers and Elite Club, Islamic Azad University, Tehran Medical Sciences Branch, Tehran, Iran.
authors.forename: Yekta
authors.initials: Y
authors.lastname: Parsa
authors.affiliation: Department of Surgery, Islamic Azad University, Tehran Medical Sciences Branch, Tehran, Iran.
authors.forename: Seyed Abbas
authors.initials: SA
authors.lastname: Mirmalek
authors.affiliation: Department of Surgery, Islamic Azad University, Tehran Medical Sciences Branch, Tehran, Iran.
authors.forename: Fatemeh Elham
authors.initials: FE
authors.lastname: Kani
authors.affiliation: Department of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran.
authors.forename: Amir
authors.initials: A
authors.lastname: Aidun
authors.affiliation: Students' Research Committee, Islamic Azad University, Tehran Medical Sciences Branch, Tehran, Iran.
authors.forename: Seyed Alireza
authors.initials: SA
authors.lastname: Salimi-Tabatabaee
authors.affiliation: Young Researchers and Elite Club, Islamic Azad University, Tehran Medical Sciences Branch, Tehran, Iran.
authors.forename: Soheila
authors.initials: S
authors.lastname: Yadollah-Damavandi
authors.affiliation: Young Researchers and Elite Club, Islamic Azad University, Tehran Medical Sciences Branch, Tehran, Iran.
authors.forename: Ehsan
authors.initials: E
authors.lastname: Jangholi
authors.affiliation: Young Researchers and Elite Club, Islamic Azad University, Tehran Medical Sciences Branch, Tehran, Iran.
authors.forename: Tina
authors.initials: T
authors.lastname: Parsa
authors.affiliation: Students' Research Committee, Baqiyatallah University of Medical Sciences, Tehran, Iran.
authors.forename: Ehsan
authors.initials: E
authors.lastname: Shahverdi
keywords: Estrogen receptor; biological markers; breast cancer; human epidermal growth factor receptor-2; progesterone receptor