title: Neoadjuvant chemotherapy-induced changes in immunohistochemical expression of estrogen receptor, progesterone receptor, HER2, and Ki-67 in patients with breast cancer.
abstract: OBJECTIVE
  The impact of neoadjuvant chemotherapy (NACT) on immunohistochemical markers in breast cancer specimens remains controversial. We designed the current study to investigate the potential changes in estrogen receptor (ER), progesterone receptor (PR), HER2, and Ki-67 expression before and after NACT in a cohort of Turkish patients with breast cancer.
  
  
  METHODS
  This research was designed as a prospective, observational study of 100 consecutive patients with breast cancer (mean age 47.8±11.4 years) who were scheduled to undergo anthracycline- and/or taxane-containing NACT before attempting cytoreductive surgery at the Department of Oncology of the Uludag University Medical Center, Bursa, Turkey. Immunohistochemistry was performed on formalin-fixed, paraffin-embedded specimens.
  
  
  RESULTS
  Changes in immunohistochemical markers before and after NACT were only significant for HER-2 and Ki- 67. More specifically, the number of HER-2-positive specimens decreased from 21 before NACT to 8 after NACT (p<0.001). Similarly, the number of tumor samples positive for Ki-67 decreased significantly from 65 to 24 after NACT (p<0.001). Mean pre- and post-treatment tumor grades of differentiation before and after NACT were 2.56 ± 0.67 and 2.37±1.07, respectively (p<0.05). We did not find any significant associations between baseline ER, PR, HER2, and Ki-67 expression with both overall survival (OS) and disease- free survival (DFS).
  
  
  CONCLUSIONS
  Our study suggests that NACT reduces the expression of HER2 and Ki-67 in breast cancer specimens. The significance of NACT-induced changes in the immunohistochemical expression of HER2 and Ki-67 in patients with breast cancer should be further studied in future translational and clinical research.
authors.affiliation: Department of Medical Oncology, Uludag University Faculty of Medicine, Bursa, Turkey.
authors.forename: Nilufer
authors.initials: N
authors.lastname: Avci
authors.forename: Adem
authors.initials: A
authors.lastname: Deligonul
authors.forename: Sahsine
authors.initials: S
authors.lastname: Tolunay
authors.forename: Erdem
authors.initials: E
authors.lastname: Cubukcu
authors.forename: Omer
authors.initials: O
authors.lastname: Fatih Olmez
authors.forename: Arife
authors.initials: A
authors.lastname: Ulas
authors.forename: Mustafa
authors.initials: M
authors.lastname: Hartavi
authors.forename: Ender
authors.initials: E
authors.lastname: Kurt
authors.forename: Turkkan
authors.initials: T
authors.lastname: Evrensel
mesh_terms: D000328:Adult; D018943:Anthracyclines / Q000008:administration & dosage; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000401:mortality / Q000473:pathology; D017024:Chemotherapy, Adjuvant; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism*; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D060787:Neoplasm Grading; D011237:Predictive Value of Tests; D011446:Prospective Studies; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*; D016019:Survival Analysis; D043823:Taxoids / Q000008:administration & dosage; D013997:Time Factors; D016896:Treatment Outcome; D014421:Turkey
chemical_list: D018943:Anthracyclines; D019394:Ki-67 Antigen; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D043823:Taxoids; C508053:ERBB2 protein, human