Cancer vaccine trials started per year. The number of trials started each year is shown. Bars represent the total number of trials started for a particular year. The color code on each bar represents the phase of the trials (green: phase 1; yellow: phase 2; red: phase 3; grey: unspecified).
Cao et al. Immunome Research 2008 4:7 doi:10.1186/1745-7580-4-7