▪Gas plasma inhibited BC cell growth and recovered drug sensitivity of Tx‐resistant MCF‐7 (MCF‐7/TxR)▪Gas plasma‐induced cell sensitivity to drug (Paclitaxel) not related to changes in drug uptake but modification of oncogene and tumour suppressor gene expression (KIF13B, CEACAM1, GOLM1, TLE4, PHKA1, DAGLA)▪Gas plasma‐induced up‐regulation of tumour suppressor DAGLA and down‐regulation of tumourigenic CEACAM▪Gas plasma decreased drug resistance and toxicity by altering colony formation and tumourigenesis in siDAGLA and siCEACAM transfected BC cells. This evidence concerns the gene CEACAM1 and breast cancer.