Abstract 4339: Progranulin (GP88) expression in thoracic maligancies

Background: GP88 (progranulin) is a growth and survival factor implicated in tumorigenesis and drug resistance for various cancers. GP88 tissue expression measured by IHC is inversely correlated with survival. We now evaluate GP88 tissue lung cancer small cell carcinoma (SCLC), non-small cell lung carcinoma (NSCLC) and mesothelioma. Methods: GP88 expression was determined by immunohistochemistry on tissue sections from normal lung, pleura, benign mesothelial proliferation, SCLC, NSCLC and mesothelioma. In the case of NSCLC, GP88 expression in tumor tissues from patients with localized (stage I-II) and locally advanced disease (IIIa-IIIb) was determined and correlated with clinical outcome disease-free survival (DFS) and overall survival (OS). Serum GP88 levels from patients with metastatic NSCLC was quantified by EIA and compared to GP88 levels from patients with COPD and from healthy individuals. Results: GP88 was significantly expressed in NSCLC (adenocarcinoma and squamous cell) and mesothelioma (epitheloid, sarcomatoid and biphasic subtypes) tumors. In contrast, normal lung tissue, benign lung disease, pleura, benign mesothelial proliferations and SCLC were negative. There was a significant increased risk of recurrence and death for patients with resected NSCLC (stage I,II) with high expression (GP88 IHC score 3+) compared to patients with GP88IHC score