## 5 Conclusions  
Breast cancer is one of the most prevalent types of invasive cancer in women. The treatment of breast cancer is obstructed by the adverse effects of existing chemotherapeutic agents, as well as the high progression of drug resistance. Plants serve as a pool of chemical entities that can assist in curbing various diseases, including cancer. Herein, pine extract and abiotic acid, its naturally extracted pure compound, were tested for their anticancer potency against MCF-7 cancer cell line and a normal cell line, WI-38. We found that abietic acid showed dose-dependent growth inhibitory effects on the MF-7 cells. Abietic acid showed relatively lower cytotoxic effects over normal WI-38 cells. These observations agreed with the few available investigations in which abietic acid was studied, showing its suppressive effects on the growth and progression of some cancer cells. Moreover, it was found that abietic acid triggered total antioxidants in MCF-7 cells. This was accompanied by diminished intrinsic oxidative stress, which is responsible for carcinogenesis and resistance of MCF-7 cells. Since apoptosis is a vital anticancer target, used to eliminate cancer cells and maintain tissue homeostasis, was carried out annexin V/PI double staining of pine extract and abietic acid on treated-MCF-7 cells and found that abietic acid triggered cell cycle arrest in MCF-7 cells in G\({}_{2}\)/M phase as well as the SubG\({}_{0}\)-G\({}_{1}\) subpopulation. Abietic acid-induced early-stage apoptosis was also accompanied by an upsurge of _caspase-3_, _caspase-8_ and _Bax_ and a decline in _Bel-2_. Abietic acid could modulate gene expression of oncogenic genes such as c-myc, _TNF-_a_ and _NF-_xB_. Abietic acid also downregulated the expression of many proliferation genes, such as _VEGF, TGF-f1_ and _IGF1R_, that are known for their potential effects on angiogenesis, proliferation, metastasis, and invasion of MCF-7 cells. All these gene markers have been reported to be essential therapeutic biochemical targets for anticancer drugs. Cytosolic cytochrome-C protein expression release was observed, with significant increases in abietic acid-treated cells. Our recommendation for future studies on abietic acid would be to carry out an in vivo study using breast cancer animal models to confirm our hypothesis and suggest the appropriate sublethal dose for future clinical studies.  
**Supplementary Materials:** The following are available online, Figure S1: Sigmoidal dose-response relation for calculation of IC\({}_{50}\) of (A) Pine extract and (B) Abietic acid on HepG-2, MCF-7 and HCT-11 cancerous cell lines and WI-38 normal cells. Table S1: Primer's sequences of apoptotic genesused for gene expression analysis, Video S1: Scanning video for immunocytochemistry fluorescence calculation of abietic acid.  
Conceptualization; H.H., H.Y.E. and Z.A.H.; Data curation; H.H., S.O. and H.Y.E. Formal analysis; H.H., S.O. and H.Y.E.; Investigation; H.H., H.Y.E. and Z.A.H.; Methodology; H.H. and H.Y.E.; Project administration; H.H.; Resources; S.O.; Software; H.H.; Supervision; Z.A.H., H.H. and H.Y.E.; Validation; H.H. and H.Y.E.; Visualization; H.H. and H.Y.E.; Roles/Writing--original draft; H.H.; Writing--review & editing, Z.A.H., H.Y.E., H.H. and S.O. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The data presented in this study are available in this article.  
Authors would like to thank [PERSON] for giving them the opportunity to use the facilities/equipment available in HSR laboratory.  
The authors declare no conflict of interest.  
Samples of the pine extract/abietic acid are available from the authors upon request.