Fig. 6

Genome-wide identification and differential expression of signature genes related to chronic adaptation to acidic microenvironment. a Hierarchical clustering heatmap of differentially expressed genes in SUIT-2 PDAC cells subjected to acute (S.A.) or chronic (L.A.) continuous acidotic pHe stress. There were 314 genes with significantly differential expression patterns (L.A. vs S.A., absolute log₂ fold-change ≥1, p < 0.05) identified and annotated either as a chronic_acidosis_adaptation up-regulated signature or chronic_acidosis_adaptation down-regulated signature. The distance used for the clustering is based on the classical Euclidean distance that allows clustering gene expression by expression levels. Note that very few genes have a differential expression pattern and are significant in the buffer (Buff) group; these were excluded. b A total of 15 differentially expressing genes (DEGs) identified from the list of chronic_acidosis_adaptation signatures that are significantly related to the overall survival of 176 pancreatic cancer patients in TCGA-PAAD cohort in a Cox regression model