Figure 4.

RE can affect all stages of carcinogenesis. RE can attenuate the various stages of cancer development, depending on its concentration. At low to moderate concentrations, RE, by acting as a chemopreventive agent, can block cancer initiation. This is achieved by suppression of spontaneous mutations and a reduction of cancer promotion that can lead to decreased tumor growth rate. At higher concentrations, RE can alter the late stages of carcinogenesis. By acting as a cytotoxic agent, RE can halt the progression and metastasis of cancer cells through the inhibition of angiogenesis and invasion of primary tumor cells. Hence, RE can be used to prevent cancer formation at its early stages or halt the progression and subsequent metastasis by acting as a cytotoxic agent [202,203,204,205,206].