Association between post-operative hPG(80) (circulating progastrin) detectable level and worse prognosis in glioblastoma

BACKGROUND: Patients with glioblastomas have a dismal prognosis, and there is no circulating predictive or prognostic biomarker. Circulating progastrin, hPG(80), is a tumor-promoting peptide present in the blood of patients with various cancers that has been shown to have prognostic value. We evaluated the prognostic value of plasma hPG(80) in patients with isocitrate dehydrogenase-wild type glioblastoma after surgery. PATIENTS AND METHODS: A multicentric retrospective study in glioblastoma patients treated with standard radio-chemotherapy was conducted. The hPG(80) levels were measured in plasma EDTA samples collected after surgery with an ELISA DxPG80.lab kit (Biodena Care, Montpellier, France), which has a detection threshold of 1.2 pM. The relationship between post-operative hPG(80) plasma levels, in combination with other known prognostic factors, and patients’ progression-free survival (PFS) and overall survival (OS) was evaluated. RESULTS: Sixty-nine patients were assessable. Plasma samples were collected after tumor biopsy (B), partial resection (PR), and complete resection (CR) for 22, 25, and 22 patients, respectively. At a median concentration of 5.37 pM (interquartile range 0.00-13.90 pM), hPG(80) was detected in 48 (70%) patients (hPG(80)+). CR was associated with significant lower values of hPG(80) levels: the median value was 0.7 versus 9.1 pM for PR (P = 0.02) and 8.3 pM for B (P = 0.004). The hPG(80) detection rate was also significantly lower: 50% (CR) versus 72% (PR) versus 86% (B) (P = 0.005). The median follow-up was 39 months [22.4 months-not reached]. hPG(80) post-operative detection was associated with numerically shorter PFS (6.4 versus 9.4 months, P = 0.13) and OS (14.5 versus 20.9 months, P = 0.11). In multivariate analysis, hPG(80) was a prognostic factor for OS (P = 0.034). CONCLUSIONS: Circulating hPG(80) could serve as a new prognostic biomarker after surgery in patients with glioblastoma treated with radio-chemotherapy.