Genetic activation of the MET pathway and prognosis of patients with high-risk, radically resected gastric cancer

Francesco Graziano, Nadia Galluccio, Paola Lorenzini, Annamaria Ruzzo, Emanuele Canestrari, Silvia D'Emidio, Vincenzo Catalano, Valerio Sisti, Claudia Ligorio, Francesca Andreoni, Eliana Rulli, Enrico Di Oto, Giammaria Fiorentini, Costantino Zingaretti, Michele De Nictolis, Federico Cappuzzo, Mauro Magnani

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose To investigate whether prognosis of patients with high-risk gastric cancer may depend on MET copy number gain (CNG) or an activating truncation within a deoxyadenosine tract element (DATE) in the promoter region of the MET ligand HGF. Patients and Methods A single-institution cohort of 230 patients with stage II/III gastric cancer was studied. Formalinfixed paraffin-embedded tumor specimens were used for DNA extraction. Quantitative polymerase chain reaction (qPCR) for MET CNG and sequencing for HGF DATE truncation (<25 deoxyadenosines instead of 30) were used. Results were analyzed for association with diseasefree survival (DFS) and overall survival (OS). To assess the reliability of the qPCR measurement, a random sample of cases was reanalyzed using an alternative assay (fluorescent in situ hybridization [FISH]) with calculation of the intracorrelation coefficient (ICC). Results In 216 assessable patients, MET CNG five or more copies and homozygous HGF-truncated DATE occurred in 21 patients (10%) and 30 patients (13%), respectively. Patients with MET CNG five or more copies (MET-positive) showed significantly worse prognosis with multivariate hazard ratio (HR) of 3.02 (95% CI, 1.71 to 5.33; P <.001) for DFS and multivariate HR of 2.91 (95% CI, 1.65 to 5.11; P <.001) for OS. The agreement between qPCR and FISH was high, with ICC = 0.9% (95% CI, 0.81% to 0.95%; the closer the ICC is to 1, the greater is the agreement). HGF-truncated DATE did not show relevant prognostic effect. Conclusion In this study, qPCR revealed approximately 10% of white patients with gastric cancer harboring MET CNG of five or more copies. This marker was significantly associated with unfavorable prognosis. This information is relevant to the current clinical development of anti-MET compounds.

Original languageEnglish
Pages (from-to)4789-4795
Number of pages7
JournalJournal of Clinical Oncology
Volume29
Issue number36
DOIs
Publication statusPublished - Dec 20 2011

ASJC Scopus subject areas

  • Cancer Research
  • Oncology

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