title: CK-19 expression by RT-PCR in the peripheral blood of breast cancer patients correlates with response to chemotherapy.
abstract: BACKGROUND
  The recent introduction of sensitive RT-PCR-based techniques for the detection of epithelial antigen expression, such as CK-19, in the peripheral blood and bone marrow of breast cancer patients may provide an opportunity to evaluate tumor response at the molecular level, even in the absence of measurable disease while patients are still receiving chemotherapy.
  
  
  METHODS
  We studied serially collected blood samples of 53 patients with breast cancer before, during, and after adjuvant, neoadjuvant, and palliative chemotherapy to evaluate its effects on the expression of CK-19 measured by RT-PCR.
  
  
  RESULTS
  The percentage of CK-19 RT-PCR positivity decreased consistently from 43% (23/53) before chemotherapy to 14.3% (7/49), and to 18.9% (7/37) after 3 and 6 cycles, respectively (chi-square for linear trend = 7.948; p = 0.0048). Furthermore, there was a significant correlation between a negative CK-19 at three months and the response to chemotherapy (p = 0.024).
  
  
  CONCLUSIONS
  We conclude that RT-PCR negativity for CK-19 expression at 3 months after the beginning of chemotherapy correlates with tumor response and, as treatment progresses, there is a significant trend for the occurrence of more negative RT-PCR results. Further studies are needed to confirm if this technique can be useful to assess response to chemotherapy in patients without measurable disease and if negativation of CK-19 expression while on chemotherapy is of prognostic significance.
authors.affiliation: Disciplina de Hematologia e Oncologia da Faculdade de Medicina da Fundação ABC, São Paulo, Brazil.
authors.forename: A R
authors.initials: AR
authors.lastname: Manhani
authors.forename: R
authors.initials: R
authors.lastname: Manhani
authors.forename: H P
authors.initials: HP
authors.lastname: Soares
authors.forename: I
authors.initials: I
authors.lastname: Bendit
authors.forename: F
authors.initials: F
authors.lastname: Lopes
authors.forename: A G
authors.initials: AG
authors.lastname: Nicoletti
authors.forename: F L
authors.initials: FL
authors.lastname: Fonseca
authors.forename: M
authors.initials: M
authors.lastname: Novaes
authors.forename: S M
authors.initials: SM
authors.lastname: Zatta
authors.forename: V
authors.initials: V
authors.lastname: Arias
authors.forename: S
authors.initials: S
authors.lastname: Giralt
authors.forename: A
authors.initials: A
authors.lastname: del Giglio
mesh_terms: D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000276:immunology*; D018450:Disease Progression; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007633:Keratins / Q000096:biosynthesis*; D008875:Middle Aged; D010166:Palliative Care; D011237:Predictive Value of Tests; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; D007633:Keratins