Fig 1: Repeatedly exposed cancer cells exhibit slow-cycling behaviour in vivo.a Experimental summary of generation of repeatedly exposed (RE) A431 cells for in vivo experiments. b Experimental procedure of animal experiments (n = 8, except WT + P (n = 7)). c Caliper measurements of tumour growth (n = 16, except WT + P (n = 14). d Growth reduction of WT and RE tumours in response to gas plasma treatment calculated from caliper measurements at day 8 (RE, n = 16; WT, n = 14), graph shows mean with individual data points, statistical analysis was performed using unpaired t test (one-tailed *P ≤ 0.05). e representative MRI images and f calculated tumour volume thereof (n = 16, except WT + P (n = 14)), bar graphs show mean and individual data points, statistical analysis was performed using one-way analysis of variance (ANOVA) (**P ≤ 0.01, ***P ≤ 0.001). g Growth reduction of WT and RE tumours in response to gas plasma treatment calculated from the area under the curve of MRI volume measurements (RE, n = 16; WT, n = 14), bar graphs show median and individual data points, statistical analysis was performed using unpaired t test (two-tailed). h Representative images of excised tumours. i Representative flow cytometry intensity histograms of calreticulin (CRT), CD152, CD155 (extracellular staining) and phosphorylated epithelial growth factor receptor (EGFR ~ P), nitrotyrosine, phosphorylated histone 2AX (yH2AX~P, intracellular staining). j WPGMA-weighted hierarchical clustering of z-scored baseline surface marker expression levels of untreated WT and RE tumours (n = 8). k Fold change of extra- (n = 7) and intracellular (n = 4) marker expression of gas plasma-exposed WT and RE tumours normalised to untreated controls, floating bars show minimum to maximum, with the mean indicated as a line. ns non-significant, WT wild type, RE repeated exposure, p plasma, ox stress oxidative stress, EMT epithelial–mesenchymal transition, UTR untreated.