Cancer is a leading cause of death and a healthcare challenge in the world. Hence, this work was conducted to determine the in vitro anticancer property and also the molecular mechanism of hydro-alcoholic extract of Carthamus lanatus L (HACL) whole plant in a human cancer cell line, THP-1 (human leukemia cell line). In vitro cytotoxic potential of the extract was examined using the standard MTT (3-(4,5-dimethylthiazole)-2,5-diphenyltetrazolium bromide) method and water-soluble tetrazolium salt (WST-1) in human leukemia cell culture. In turn, the gene expression levels of B-cell lymphoma 2 (Bcl-2), tumor necrosis factor-alpha (TNFα), interleukin 6 (IL-6), cysteine-dependent aspartate-specific peptidase (Caspase 3 and 8) and programmed cell death 4 were assessed by applying RT-qPCR. The MTT and WST-1 assays data showed that the hydro-alcoholic extract of C. lanatus had an antiproliferative effect on human leukemia with IC50 of 523.5±2.23 and 497.23±3.15 µg/mL, respectively. The gene expression levels of tumor necrosis TNFα, IL-6, Bcl-2, PDCD4, Caspase 3, and caspase 8 were assessed by applying RT-qPCR. Our data showed that HCAL induces anticancer effect by down-regulating the anti-apoptotic (Bcl-2) and pro-inflammatory (IL-6 and TNFα) genes expression. On the contrary, pro-apoptotic PDCD4, caspase 3 and caspase 8 genes were significantly up-regulated in THP-1 cells. However, based on the up-regulation of caspases, two distinct types of apoptotic pathways are proposed. The extrinsic pathway's or ROS's production involvement, however, cannot be excluded. It would be necessary to do more research to demonstrate these constituents using a bioguided fractionation. This will enable the isolation, identification of the active principles responsible of other regulators/signals involved in the cytotoxic and apoptotic effect of the C. lanatus extract, and the elucidation of their mechanism of action.