ISSN : 2146-3123
E-ISSN : 2146-3131

PTK-7 Expression in Gastric Cancer: A Prognostic Determinant
Melike Özçelik1, Özlem Ercelep2, Sevinç Keser3, Nagehan Özdemir Barışık3, Merve Başar3, Hatice Odabaş2, Abdilkerim Oyman2, Selver Işık2, Serhat Özçelik4, Mehmet Aliustaoğlu2
1Department of Medical Oncology, University of Health Sciences, İstanbul Ümraniye Training and Research Hospital, İstanbul, Turkey
2Department of Medical Oncology, Dr. Lütfi Kırdar Training and Research Hospital, İstanbul, Turkey
3Department of Pathology, Dr. Lütfi Kırdar Training and Research Hospital, İstanbul, Turkey
4Department of Endocrinology and Metabolism, Dr. Lütfi Kırdar Training and Research Hospital, İstanbul, Turkey
DOI : 10.4274/balkanmedj.galenos.2019.2019.8.12

Background: Protein tyrosine kinase-7 (PTK-7), a regulator protein in the Wnt signaling pathway was found to be highly over-expressed in various cancer types and assumed to be related with prognosis.
Aim: The purpose of this study is to assess whether PTK-7 expression status in curatively resected gastric carcinoma, would indepedently identify patients with a high risk of recurrence and death.
Study Design: Retrospective follow-up study.
Methods: We included patients who were at least 18 years of age and diagnosed with gastric cancer. Exclusion criteria was metastatic disease at the time of diagnosis or operation. Data on clinicopathological prognostic determinants and clinical course including the date of disease relapse and survival status were collected with the use of medical records. Surgically removed tumor tissue specimen was examined by two independent pathologists at the pathology department of our institution. PTK-7 expression status was assessed with immunohistochemical processing and stratified on a scale ranging from 0 to +3 according to the extent of stained tumor cells. It was then further categorized into 2 groups, one being + (positive); including +1, +2 and +3 scores, another was – (negative); including – and +/- scores.
Results: A total of 114 patients were analyzed. PTK-7 expression was present in 66.7% of the surgical tumor specimens. . There was no statistically significant difference in almost all of the relevant parameters between the PTK-7 positive and negative groups. The estimated median survival in the PTK-7 positive group was significantly better than the PTK-7 negative group (60 vs. 22 months, p<0.001). Likewise disease-free survival was found to be 55 months in the PTK-7 positive group whereas 21 months in the negative group (p=0.015). In the multivariate analysis, along with negative PTK-7 expression, poor performance status and advanced stage were significantly associated with the risk of death (p<0.001 for each).
Conclusion: Based on the analysis of PTK-7 expression status among surgically resected gastric tumor samples, this study documented that positive PTK-7 expression led to longer DFS and OS times compared to negative expression. Efforts should be made to enhance this finding and translate it to the clinical practice.

Keywords : gastric cancer, prognostic factor, PTK-7
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