title: Diagnostic and prognostic roles of DOG1 and Ki-67, in GIST patients with localized or advanced/metastatic disease.
abstract: OBJECTIVE
  Gastrointestinal stromal tumor is the most common mesenchymal neoplasia in the gastrointestinal tract and has a broad spectrum of pathological patterns and also clinical features changing from benign to malignant. Although the well-characterized parameters to predict the outcome have been the size and the mitotic index of the tumor in the patients with early-staged disease, bulky recurrent or metastatic tumor, resistance to medical treatment and mutation analysis are the prognostic factors for advanced stage-GIST. The aim of this study is to investigate new and more practical tissue markers, such as DOG1 and Ki-67 to specify the GIST diagnosis and also to predict the outcome in GIST patients with both localized and advanced staged disease.
  
  
  METHODS
  For the last 14 years, from 1999 to 2013, 111 patients with a histopathological GIST diagnosis from the hospital files were enrolled to the study. In their parafin-embedded tissue samples, DOG1 and Ki-67 expressions were evaluated with immunohistochemisty by two independent pathologists from Cukurova University Medical Faculty. Patients were divided into two groups, the patients with localized disease treated by surgery and the patients with advanced/metastatic disease. DOG1 and Ki-67 expressions were corelated with other diagnostic and prognostic histopathological markers and also the clinical outcome in these two group of patients.
  
  
  RESULTS
  The specificity and the sensitivity of DOG1 in GIST diagnosis was found 94 and 43%, respectively. DOG1 expression was especially important in the diagnosis of c-kit negative cases. Although Ki-67 was not found a statistically significant prognostic factor for overall survival, it was strongly corelated with mitotic index which is a well-known standart prognostic factor for localized disease.
  
  
  CONCLUSIONS
  DOG1 seems to be an important diagnostic tool for clinically suspected GIST diagnosis in both advanced or early staged patients whose tumours are c-kit expression negative. On the other hand, Ki-67 can be a stronger candidate for prognostic factor instead of mitotic index to identify the proliferative cells out of mitotic phase but this statement needs be prospectively validated on studies with large number of patients.
authors.affiliation: Department of Internal Medicine, Iskenderun State Hospital Hatay, Turkey.
authors.forename: Didem
authors.initials: D
authors.lastname: Sözütek
authors.affiliation: Department of Patology, Iskenderun State Hospital Hatay, Turkey.
authors.forename: Serdar
authors.initials: S
authors.lastname: Yanık
authors.affiliation: Department of Family Medicine, Iskenderun State Hospital Hatay, Turkey.
authors.forename: Ayşe Neslin
authors.initials: AN
authors.lastname: Akkoca
authors.affiliation: Department of General Surgeons and Gastroenterology, Mersin State Hospital Mersin, Turkey.
authors.forename: Alper
authors.initials: A
authors.lastname: Sözütek
authors.affiliation: Department of Internal Medicine, Bozok University Medical School Yozgat, Turkey.
authors.forename: Zeynep Tuba
authors.initials: ZT
authors.lastname: Ozdemir
authors.affiliation: Department of Medical Oncology, Çorlu Statae Hospital Tekirdağ, Turkey.
authors.forename: Ciğdem Usul
authors.initials: CU
authors.lastname: Avşar
authors.affiliation: Department of Medical Oncology Dr. Sadi Konuk Research Hospital İstanbul, Turkey.
authors.forename: Meral
authors.initials: M
authors.lastname: Günaldı
authors.affiliation: Department of Medical Oncology, Cukurova University Medical School, Internal Medicine Adana, Turkey.
authors.forename: Berksoy
authors.initials: B
authors.lastname: Sahin
authors.affiliation: Department of Patology, Cukurova University Medical School Adana, Turkey.
authors.forename: Figen
authors.initials: F
authors.lastname: Doron
keywords: DOG1; Gastrointestinal stromal tumor; Ki-67; prognostic factor