“…The included studies were carried out worldwide, including in the USA ( n = 30) ( 24–53 ), Europe ( n = 10) ( 20 , 54–62 ), Canada ( n = 4) ( 63–66 ), Malaysia ( n = 4) ( 67–70 ), Australia ( n = 6) ( 71–76 ), Brazil ( n = 2) ( 77 , 78 ), China ( n = 2) ( 79 , 80 ), Iran ( n = 2) ( 81 , 82 ), Korea ( n = 1) ( 83 ), Taiwan ( n = 1) ( 84 ), Japan ( n = 1) ( 85 ), and Ethiopia ( n = 1) ( 86 ). A total of 47,964,650 cancer patients participated in a total of 64 studies carried out worldwide, with study samples ranging from 26 to 19.6 million.…”