Dandelion Root is frequently used by herbalists to treat liver, kidney, and gallbladder problems. It has been used in China for certain kinds of cancers for centuries. It is incredibly high in potassium and Vitamin A, among other things.
Dandelion Root has been a focus of study for its ability to improve liver and gallbladder function, as well as stimulate appetite. And right now, human clinical trials are taking place to evaluate how Dandelion Root extract might help in treating blood-related cancers, including lymphoma and leukemia. 
Laboratory studies have shown dandelion to have anticancer properties, but clinical studies have not shown this effect in humans. Dandelion Root extract has anticancer effects against melanoma, leukemia, pancreatic cancer, and colorectal cancer cell lines. However, human studies are limited. 
Researchers from Windsor Regional Cancer Centre in Canada announced in February 2015 that approval and funding for human clinical trials on dandelion's anti-cancer potential had been received. The researchers are testing a potent form of Dandelion Root extract on a group of 30 patients with end-stage, blood-related cancers.
The University of Maryland Medical Center has also noted that the dandelion flower, in particular, possesses strong antioxidant properties which are helpful in averting cancer. Earlier research by Dr. Siyaram Pandey from the University of Windsor further illustrates the anti-cancer potential of dandelion. In otherwise untreatable pancreatic cancer (which is said to have close to a 100 percent mortality rate), Dandelion Root extract was found to induce programmed cell death, also known as apoptosis, in pancreatic cancer cells. It also killed leukemia and melanoma cancer cells in lab mice. Dandelion Root extract similarly induced autophagy, a process by which the body maintains homeostasis through the proper elimination of damaged or malignant cells. 
“BxPC-3 and PANC-1 pancreatic cells were sensitive to aqueous DRE (Dandelion Root extract). This extract induces selective apoptosis in a dose- and time-dependent manner. Dandelion Root extract caused the collapse of the mitochondrial membrane potential, leading to prodeath autophagy. Normal human fibroblasts were resistant at similar doses,” the study stated.
“We demonstrated that DRE has the potential to induce apoptosis and autophagy in human pancreatic cancer cells with no significant effect on noncancerous cells. This will provide a basis on which further research in cancer treatment through DRE can be executed.” 
Thus, while promising results have been reported, additional studies are needed to understand the effectiveness of dandelion root in cancer patient treatment.