PracticeUpdate: Haematology & Oncology

SABCS 2016 29

© MedMeetingImages/Todd Buchanan 2016

Circulating levels of GP88 in patients with metastatic breast cancer correlate with OS C irculating levels of GP88 in patients with metastatic breast cancer have been shown to correlate with overall 88kDa glycoprotein progranulin (GP88). GP88 is expressed in tumour tissue, not in normal mammary tissue, and is secreted into the circulation of patients with breast cancer. GP88 is a critical driver of breast cancer cell proliferation, survival, invasiveness, and drug resistance.

Measuring circulating GP88 levels would provide additional information to that available in today’s standard of care for monitoring.

survival. It would appear that patients whose GP88 can be maintained below 60 ng/mL survive longer, finds a correlative study of serum progranulin (GP88) with circulating tumour cells from patients with metastatic breast cancer. Ginette Serrero, PhD, of A & G Pharmaceu- tical Inc., Columbia, Maryland, explained that imaging technologies are the methods of choice to monitor therapeutic response in patients with metastatic breast cancer. Such methods are expensive, however, and their sensitivity to detect disease response in a timely manner is limited. Measurement of circulating tumour markers such as CA15-3, CA27.29 and carcinoembry- onic antigen has offered additional minimally invasive methods for monitoring response to treatment for metastatic breast cancer. While useful, their ability to provide clinicians with real-time disease monitoring is limited. Understanding real-time biological processes may lead to better biomarkers of the disease state and aid real-time clinical management of metastatic breast cancer by identifying circulating disease-associated biomarkers. Dr Serrero and colleagues characterised a target biomarker that would meet these criteria, the

at –80°C until tested for GP88 using a GP88 enzyme-linked immunoassay. Statistical analysis using Kaplan-Meier func- tions was used to assess whether GP88 serum level and overall survival were correlated in patients with metastatic breast cancer. By analysing the Kaplan-Meier plots at different GP88 cut points, two populations were iden- tified with distinct survival characteristics. When examined in more detail, the differ- ence in overall survival of patients with < and >60 ng/mL was statistically significant (P = 0.0002). Dr Serrero concluded that circulating levels of GP88 in patients with metastatic breast cancer correlate with overall survival. It would appear that patients whose GP88 can be maintained below 60 ng/mL survive longer. Measuring circulating GP88 levels would provide additional information to that available in today’s standard of care for monitoring. This valuable insight into real- time disease status will assist clinicians in patient management.

Clinical studies have demonstrated that elevated GP88 levels in tumours levels were prognostic of recurrence. Patients with breast cancer patients have been shown to harbour significantly higher GP88 serum levels than healthy individuals. Using tissue and serum testing to detect and quantify GP88 could provide a new strategy for identifying patients with breast cancer at high risk of recurrence and for monitoring disease progression Dr Serrero and colleagues set out to de- termine whether GP88 serum levels were elevated in patients with metastatic breast cancer and whether these levels correlate with patient overall survival. Ninety-two patients with metastatic breast cancer who were undergoing therapy at a single clinic were screened for clinical and disease characteristics along with serum CA15-3 values. Serum samples were collect- ed from each patient during therapy and all patients were monitored. Serum was stored

PracticeUpdate Editorial Team

VOL. 2 • NO. 1 • 2017