title: Detection of KRAS mutations in circulating tumor cells from patients with metastatic colorectal cancer.
abstract: BACKGROUND
  Quantification of Circulating Tumor Cells (CTCs) as a prognostic marker in metastatic colorectal cancer (mCRC) has already been validated and approved for routine use. However, more than quantification, qualification or characterization of CTCs is gaining importance, since the genetic characterization of CTCs may reflect, in a real time fashion, genetic profile of the disease.
  
  
  OBJECTIVE
  To characterize KRAS mutations (codon 12 and 13) in CTCs from patients with mCRC and to compare with matched primary tumor. Additionally, correlate these mutations with clinical and pathological features of patients.
  
  
  METHODS
  Blood samples were collected from 26 patients with mCRC from the AC Camargo Cancer Center (São Paulo-Brazil). CTCs were isolated by ISET technology (Isolation by Size of Epithelial Tumors; Rarecells Diagnostics, France) and mutations analyzes were performed by pyrosequencing (QIAGEN).
  
  
  RESULTS
  KRAS mutation was detected in 7 of the 21 cases (33%) of samples from CTCs. In matched primary tumors, 9 of the 24 cases (37.5%) were found KRAS mutated. We observed that 5 of the 9 samples with KRAS mutation in their primary tumor had also KRAS mutation in CTCs, meaning a concordance of 71% of matched cases (P = 0.017). KRAS mutation neither on primary tumor nor in CTCs was associated with clinical-pathological parameters analyzed.
  
  
  CONCLUSIONS
  Faced with a polyclonal disease like colorectal cancer, which is often treated with alternating and successive lines of chemotherapy, real time genetic characterization of CTCs, in a fast and feasible fashion, can provide important information to clinical management of metastatic patients. Although our cohort was limited, it was possible to show a high grade of concordance between primary tumor and CTCs, which suggests that CTCs can be used as surrogate of primary tumors in clinical practice, when the knowledge of mutation profile is necessary and the primary tumor is not available.
authors.affiliation: a International Reserch Center; AC Camargo Cancer Center ; São Paulo , Brazil.|b Department of Health ; Universidade Nove de Julho ; São Paulo , Brazil.
authors.forename: Marcilei Ec
authors.initials: ME
authors.lastname: Buim
authors.affiliation: c Department of Clinical Oncology ; AC Camargo Cancer Center ; São Paulo , Brazil.
authors.forename: Marcello F
authors.initials: MF
authors.lastname: Fanelli
authors.affiliation: c Department of Clinical Oncology ; AC Camargo Cancer Center ; São Paulo , Brazil.
authors.forename: Virgilio S
authors.initials: VS
authors.lastname: Souza
authors.affiliation: a International Reserch Center; AC Camargo Cancer Center ; São Paulo , Brazil.
authors.forename: Juliana
authors.initials: J
authors.lastname: Romero
authors.affiliation: a International Reserch Center; AC Camargo Cancer Center ; São Paulo , Brazil.
authors.forename: Emne A
authors.initials: EA
authors.lastname: Abdallah
authors.affiliation: c Department of Clinical Oncology ; AC Camargo Cancer Center ; São Paulo , Brazil.
authors.forename: Celso Al
authors.initials: CA
authors.lastname: Mello
authors.affiliation: a International Reserch Center; AC Camargo Cancer Center ; São Paulo , Brazil.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Alves
authors.affiliation: a International Reserch Center; AC Camargo Cancer Center ; São Paulo , Brazil.
authors.forename: Luciana Mm
authors.initials: LM
authors.lastname: Ocea
authors.affiliation: a International Reserch Center; AC Camargo Cancer Center ; São Paulo , Brazil.
authors.forename: Natália B
authors.initials: NB
authors.lastname: Mingues
authors.affiliation: d Department of Image ; AC Camargo Cancer Center ; São Paulo , Brazil.
authors.forename: Paula Nvp
authors.initials: PN
authors.lastname: Barbosa
authors.affiliation: d Department of Image ; AC Camargo Cancer Center ; São Paulo , Brazil.
authors.forename: Chiang J
authors.initials: CJ
authors.lastname: Tyng
authors.affiliation: d Department of Image ; AC Camargo Cancer Center ; São Paulo , Brazil.
authors.forename: Rubens
authors.initials: R
authors.lastname: Chojniak
authors.affiliation: a International Reserch Center; AC Camargo Cancer Center ; São Paulo , Brazil.
authors.forename: Ludmilla Td
authors.initials: LT
authors.lastname: Chinen
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000556:secondary; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology; D004252:DNA Mutational Analysis; D018450:Disease Progression; D005260:Female; D056726:Genetic Association Studies; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D009154:Mutation; D009360:Neoplastic Cells, Circulating / Q000473:pathology; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics*
chemical_list: C117307:KRAS protein, human; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; D016283:Proto-Oncogene Proteins p21(ras)
keywords: KRAs mutation; circulating tumor cell; colorectal cancer