In another similar study that also focused on various types of malignancy, including 146 breast cancer patients, but without a control group, serum GDF-15 was identified as a biomarker that was significantly associated with all-cause mortality [adjusted hazard ratio (HR)=5.47 (95% CI:2.66–11.24; p<0.001] (43). Here, GDF15 is linked to breast cancer.