Please use this link to access this publication. Abstract Medical marijuana has been approved by the FDA for treating chemotherapy-induced nausea and vomiting. However, less is known about its direct effects on tumor cells and the tumor microenvironment. In this study, RNA-sequencing datasets in the NCBI GEO repository were first analyzed; upregulation of cannabinoid receptors was observed in both primary and metastatic colorectal cancer (CRC) tumor tissues. An increase of cannabinoid receptors was also found in patients with CRC, azoxymethane/dextran sulfate sodium-induced CRC and CRC metastatic mouse models. Δ9-Tetrahydrocannabinol (Δ9-THC)-induced tumor progression in both primary and metastatic mouse models and also increased angiogenesis. A...