The immunohistochemical analysis of patients with synchronous GIST and another primary tumor C-KIT was positive in 7/7 cases (100%), CD-34 in 7/7 cases (100%), SMA was positive in 2/7 cases (29%), S-100 was positive in 4/7 cases (57%), DOG1 was positive in 5/7 cases (71%), DOG1 was positive in 5/7 cases (71%) and Vimentin was positive 2/7 cases (29%) (Table 3). The gene discussed is CD34; the disease is gastrointestinal stromal tumor.