The 29-kb tandem inverted duplication of Glutathione S-transferase Theta 2 (GSTT2) gene, a gene encoding an enzyme for cellular detoxification and thus showing association with cancer [42], [43], [44], [45], is preserved in chimpanzees, whereas a large deletion polymorphism involving one copy of duplicates is very common in humans: 63% in Caucasian, 47% in Yoruban and 50% in Japanese and Chinese (from HapMap Samples) [46]. Here, GSTT2 is linked to cancer.