Malignant tumors have become the leading cause of death, accounting for almost 10 million deaths worldwide in 2020. Currently, the treatment available for cancer includes radiotherapy, chemotherapy, surgery, and targeted therapy. Compared with the increasing incidence, lethal malignancies are relatively less curable with current therapies, for recurrence or metastasis occurs in a majority of patients. Therefore, it is necessary to identify more alternative therapeutic approaches to resolve the present anticancer dilemma. Since ancient times, chemical compounds derived from natural products have been used extensively for the prevention and treatment of various diseases. Paclitaxel, an anticancer drug derived from Pacific yew, represents one of the most successful clinical applications of natural compounds. The Food and Drug Administration (FDA) has approved its use in combination with cisplatin for patients with AIDS-related Kaposi's sarcoma, ovarian and breast cancer, and patients who cannot undergo surgery with/without radiotherapy for lung cancer. This success has triggered an upsurge in the study of plant-derived compounds in the treatment of malignancies. Along with exploring a variety of organisms and applying new technologies, potential bioactive compounds extracted from natural products have received an increased amount of attention regarding their use in cancer treatment. Substantial evidence indicates that natural products can be used as adjuvants to current therapies and perhaps reduce side effects in the patient. Such products could also enhance drug action to reduce the dosage and costs of chemotherapy or radiation therapy.

However, some shortcomings including constraints of stability and low efficiency in vivo have limited its large-scale clinical application. Importantly, the use of natural products as they are born without modification by pharmaceutical chemistry, is not applicable for the treatment of malignancies in humans without additional risk. Depending on the dose administered, any xenobiotic substance can induce cancer cell death in vitro. Therefore, it would be more useful to evaluate the interactions of natural compounds with the signaling pathways responsible for tumor aggressiveness in light of whether or not the natural molecule is chemically modified.

This Special Issue aims to collect original research and review articles regarding the approaches based on natural compounds in the treatment of cancer. Researchers and clinicians are invited to submit basic, translational, or clinical research articles investigating the pharmacology, pharmacodynamics, pharmacokinetics, and toxicology of natural compounds in the treatment of malignant diseases. Studies on new drug delivery systems in cancer are also welcome.

Potential topics include but are not limited to the following:

• Pharmacology of natural compounds in cancer
• Pharmacodynamics of natural compounds in cancer
• Pharmacokinetics of natural compounds in cancer
• Toxicology of natural compounds in cancer
• Design of novel drugs derived from natural compounds
• Novel delivery system for natural compounds
• Isolation of antitumor compounds from natural products
• Bioinformatics analyzing the application of natural compounds in cancer treatment
• Transcriptomics involved in antitumor effects of natural compounds
• Proteomics involved in antitumor effects of natural compounds