Biomarkers

Tumor mutation frequency or HER2 copy number amplification plus mutations in genes on the RTK, Ras or PI3K pathways could help predict responses to immunotherapy, platinum-based chemotherapy or Herceptin trastuzumab in metastatic esophagogastric cancer. In 40 patients receiving immunotherapy, high frequencies of tumor mutations in a panel of 341 cancer-associated genes were associated with poor overall survival. In 187 patients receiving platinum-based chemotherapies, high frequencies of tumor mutations in microsatellite repetitive DNA sequences were associated with poor progression-free survival. In 46 HER2-positive patients receiving Herceptin, the combination of HER2 copy number amplifications and tumor mutations in RTK, Ras or PI3K pathway genes was associated with poor progression-free survival. Next steps could include validating the markers in a larger cohort of metastatic esophagogastric cancer patients...