Since the initial work, a decade ago that the combination of C-reactive protein and albumin, the Glasgow Prognostic Score (GPS), had independent prognostic value in patients with cancer, there have been more than 60 studies (>30,000 patients) that have examined and validated the use of the GPS or the modified GPS (mGPS) in a variety of cancer scenarios. The present review provides a concise overview of these studies and comments on the current and future clinical utility of this simple objective systemic inflammation-based score. The GPS/mGPS had independent prognostic value in (a) unselected cohorts (4 studies, >19,400 patients) (b) operable disease (28 studies, >8,000 patients) (c) chemo/radiotherapy (11 studies, >1500 patients) (d) inoperable disease (11 studies, >2,000 patients). Association studies (15 studies, >2,000 patients) pointed to an increased GPS/mGPS being associated with increased weight and muscle loss, poor performance status, increased comorbidity, increased pro-inflammatory and angiogenic cytokines and complications on treatment. These studies have originated from 13 different countries, in particular the UK and Japan. A chronic systemic inflammatory response, as evidenced by the GPS/mGPS, is clearly implicated in the prognosis of patients with cancer in a variety of clinical scenarios. The GPS/mGPS is the most extensively validated of the systemic inflammation-based prognostic scores and therefore may be used in the routine clinical assessment of patients with cancer. It not only identifies patients at risk but also provides a well defined therapeutic target for future clinical trials. It remains to be determined whether the GPS has prognostic value in other disease states. Copyright © 2012 Elsevier Ltd. All rights reserved.