GDF15 and non-small cell lung carcinoma: Notably, serum GDF15 levels in the TRACERx cohort (median age 70 years) were higher than previously published in age-matched non-cancer volunteers (60-70 years, median plasma GDF15 levels of 866 pg/ml) and in keeping with previous reports of increased circulating GDF15 in patients with NSCLC 46–49.