When new blood and lymphatic vessels form from pre- existing ones, it's through a process called angiogenesis which is known for playing a critical role in the development of cancer and the growth of tumors. However, the chemical compounds found in cannabis exert an inhibitory action on the proliferation of various cancer cell lines and slows or stops the growth in tumors. Check out the articles below for more information:

Diabetic retinopathy: Role of inflammation and potential therapies for anti-inflammation (full– 2010) http://www.wjgnet.com/1948-9358/full/v1/i1/12.htm
Endocannabinoid-like N-arachidonoyl serine is a novel pro-angiogenic mediator (full – 2010)http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2936832/
Angiogenesis: a new physiological role for N-arachidonoyl serine and GPR55? (full – 2010)http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2936831/
Genetic and pharmacological inactivation of cannabinoid CB1 receptor inhibits angiogenesis (full – 2011)http://bloodjournal.hematologylibrar...7/20/5541.long
Novel hexahydrocannabinol analogs as potential anti-cancer agents inhibit cell proliferation and tumor angiogenesis (abst – 2011)http://www.ncbi.nlm.nih.gov/pubmed/20950604
Cannabidiol inhibits angiogenesis by multiple mechanisms (full – 2012) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3504989/
Cannabinoid receptor 2 agonist ameliorates mesenteric angiogenesis and portosystemic collaterals in cirrhotic rats (full – 2012)http://onlinelibrary.wiley.com/doi/1...hep.25625/full
Anti-proliferative and Anti-angiogenic Effects of CB2R Agonist (JWH-133) in Non small Lung Cancer Cells (A549) and Human Umbilical Vein Endothelial Cells: an in Vitro Investigation (abst – 2012) http://www.ncbi.nlm.nih.gov/pubmed/22578958
Autophagy triggered by magnolol derivative negatively regulates angiogenesis (full – 2013)http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3920944/
Magnolol inhibits angiogenesis by regulating ROS-mediated apoptosis and the PI3K/AKT/mTOR signaling pathway in mES/EB-derived endothelial-like cells (full – 2013) http://www.spandidos-publications.com/ijo/43/2/600
Suppression of vascular endothelial growth factor expression by cannabinoids in a canine osteosarcoma cell line (link to PDF – 2013)http://www.dovepress.com/suppression...y-cannaba13597
Magnolol suppresses vascular endothelial growth factor-induced angiogenesis by inhibiting ras-dependent mitogen-activated protein kinase and phosphatidylinositol 3-kinase/akt signaling pathways (abst + 1st page – 2013)http://www.tandfonline.com/doi/abs/1...ubmed&#preview
A new strategy to block tumor angiogenesis by inhibiting endocannabinoid inactivation (abst – 2013)http://www.fasebj.org/cgi/content/me...c-38c0c63c19ad
Blockade of cannabinoid receptors reduces inflammation, leukocyte accumulation and neovascularization in a model of sponge-induced inflammatory angiogenesis (abst – 2013) http://www.ncbi.nlm.nih.gov/pubmed/23722450
Magnolol suppresses hypoxia-induced angiogenesis via inhibition of HIF-1α/VEGF signaling pathway in human bladder cancer cells (abst – 2013) http://www.ncbi.nlm.nih.gov/pubmed/23416116
Anandamide inhibits breast tumor-induced angiogenesis (full – 2014) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4140423/
Evaluation of anti-HIF and anti-angiogenic properties of honokiol for the treatment of ocular neovascular diseases (full – 2014)http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4244131/
Cannabinoids as therapeutic agents in cancer: current status and future implications (link to PDF- 2014)http://www.impactjournals.com/oncota...e&op=view&path[]=2233
Cannabinoids as therapeutic agents in cancer: current status and future implications (link to PDF – 2014)http://www.impactjournals.com/oncota...e&op=view&path[]=2233
Cannabinoids inhibit angiogenic capacities of Endothelial cells via release of Tissue inhibitor of matrix metalloproteinases-1 from lung cancer cells (abst – 2014) http://www.ncbi.nlm.nih.gov/pubmed/24976505
Hypoximimetic activity of N-acyl-dopamines. N-arachidonoyl-dopamine stabilizes HIF-1α protein through a SIAH2-dependent pathway (abst – 2014) http://www.ncbi.nlm.nih.gov/pubmed/25090972
New insights into antimetastatic and antiangiogenic effects of cannabinoids (abst – 2015) http://www.ncbi.nlm.nih.gov/pubmed/25619715