title: Pyrosequencing evaluation of low-frequency KRAS mutant alleles for EGF receptor therapy selection in metastatic colorectal carcinoma.
abstract: OBJECTIVE
  To evaluate whether pyrosequencing (PS) improves the KRAS mutational status predictive value.
  
  
  METHODS
  A retrospective analysis of KRAS mutations by PS and direct sequencing (DS) in 192 metastatic colorectal carcinomas (mCRCs), subgrouped in 51 KRAS mutated at PS and 141 KRAS wild-type at DS.
  
  
  RESULTS
  DS failed to detect low-frequency KRAS mutations in four out of 51 mCRCs, whereas PS detected 12 additional low-frequency KRAS mutations in 141 mCRCs KRAS wild-type at DS. After reanalyzing by PS 97 KRAS wild-type tumors treated with anti-EGF receptor (EGFR) antibodies, nine additional mutations were revealed in nonresponders, whereas none of responders exhibited a KRAS-mutated genotype. Of note, KRAS-mutated tumors upon PS showed a worst progression-free survival after EGFR therapy. Finally, PS allowed the detection of additional NRAS, BRAF and exon 20 PIK3CA mutations mostly in KRAS wild-type mCRCs resistant to EGFR therapy.
  
  
  CONCLUSIONS
  PS detection of low-frequency mutations may improve the KRAS predictive value for EGFR therapy selection.
authors.affiliation: Molecular Biology Laboratory, Riuniti Hospital, Foggia, Italy.
authors.forename: Maria Iole
authors.initials: MI
authors.lastname: Natalicchio
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Improta
authors.forename: Angela
authors.initials: A
authors.lastname: Zupa
authors.forename: Olga Elisabetta
authors.initials: OE
authors.lastname: Cursio
authors.forename: Emanuela
authors.initials: E
authors.lastname: Stampone
authors.forename: Luciana
authors.initials: L
authors.lastname: Possidente
authors.forename: Assunta Maria
authors.initials: AM
authors.lastname: Teresa Gerardi
authors.forename: Giulia
authors.initials: G
authors.lastname: Vita
authors.forename: Maurizio
authors.initials: M
authors.lastname: Martini
authors.forename: Alessandra
authors.initials: A
authors.lastname: Cassano
authors.forename: Claudia
authors.initials: C
authors.lastname: Piccoli
authors.forename: Sante
authors.initials: S
authors.lastname: Romito
authors.forename: Michele
authors.initials: M
authors.lastname: Aieta
authors.forename: Raffaele
authors.initials: R
authors.lastname: Antonetti
authors.forename: Carlo
authors.initials: C
authors.lastname: Barone
authors.forename: Matteo
authors.initials: M
authors.lastname: Landriscina
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D061067:Antibodies, Monoclonal, Humanized / Q000008:administration & dosage; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000473:pathology; D018572:Disease-Free Survival; D066246:ErbB Receptors / Q000037:antagonists & inhibitors* / Q000276:immunology; D005260:Female; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009362:Neoplasm Metastasis / Q000235:genetics*; D011379:Prognosis; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins / Q000235:genetics*
chemical_list: D061067:Antibodies, Monoclonal, Humanized; C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; D066246:ErbB Receptors; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins