Region-Specific Dok2 Overexpression Associates with Poor Prognosis in Human Astrocytoma

Astrocytoma is the most frequent malignancies of the brain. Despite present clinical advancements, median survival time in malignant forms remains poor. Downstream of kinase protein 2 (Dok2) is adaptor protein known to modulate the effect of tyrosine kinase. Previously, Dok2 is shown to be marker of poor prognosis in colorectal and gastric cancer, and reduced levels of Dok2 were reported in lung adenocarcinoma and gastric cancer. The aim of the present study was to evaluate prognostic significance of pDok2 expression in surgically resected astrocytoma tissue samples. In the present study, 47 numbers of tissue samples were collected from patients who underwent surgery for astrocytoma. Temporal lobe epilepsy tissues were used as control. Real-time PCR was used to study transcript expression while protein expression was studied by western blotting and immunohistochemistry. The pDok2 expression was categorized as pDok2 positive and pDok2 negative on the basis of intensity of protein expression. This observation was confirmed by two independent pathologists. Control and few GII tissues were used as reference on account for low expression of pDok2 protein. Basic information of patients as anatomic origin of tumor and follow-up details were retrieved from hospital registry. Kaplan-Meier test was used to analyze the association of pDok2 expression and survival outcome in clinical cases. Real-time PCR signifies pDok2 is overexpressed in high-grade (GIII + GIV) tissue samples compared with low-grade (GII) and control brain tissue samples ( p