Fig. 5

Gene expression pattern in pre-treatment biopsied tissues of patients who underwent preoperative chemotherapy. a Flow diagram presenting the study scheme for the comparison of gene expression patterns in the pre-treatment biopsied gastric cancer tissues between patients in the chemotherapy response and non-response groups. b Heatmap showing the top nine genes, including interleukin-6 (IL-6), usually those associated with the extracellular matrix layer, and the expression pattern of these genes appropriately clustered into the response and non-response patient groups. A list of upregulated genes is shown for the non-response group when gene expression was evaluated in biopsied tissues from primary tumors of pretreated gastric cancer patients c Representative micrograph of IL-6 immunohistochemical staining of gastric cancer tissues showing IL-6 expression specifically in the stromal cells (black arrows), but not in the cancer cells. Scale bar = 100 μm. d Disease-free survival assessed using the GSE15459 gastric cancer dataset at www.kmplot.com. The difference in survival relative to IL6 mRNA expression was compared in each group involving all patients, i.e., those treated with surgery only and those treated with surgery and adjuvant chemotherapy, according to Kaplan-Meier survival analysis with log-rank test