INS and cancer: Epidemiological studies have also found a positive correlation between insulin levels and risk of various cancers, such as colon, breast, and endometrial cancers (Maggino et al, 1993; Gamayunova et al, 1997; Troisi et al, 1997; Del Giudice et al, 1998; Schoen et al, 1999; Josefson, 2000; Kaaks et al, 2000; Yang et al, 2001; Goodwin et al, 2002).