TP53 and neoplasm: Our results also show khat chewing to significantly increase p53 in both the control group and BC patients, which is in line with those results reporting khat to induce the tumor suppressor and cellular stress sensor p53 expression in normal human oral keratinocytes and oral fibroblasts34 and human ovarian adenocarcinoma SKOV3 cell line35 and facilitate apoptosis by a p53-dependent manner34.