Relationship between SUVmax of 18F-FDG PET/CT and serum YKL-40 levels in breast cancer

INTRODUCTION: This investigation aimed to study the differences in tumor maximum standardized uptake values (SUVmax) in breast cancer patients and compare serum levels of YKL-40, an inflammatory glycoprotein found at high levels in patients with different types of cancer, with healthy controls.
METHODS: Fifty-one women who underwent 18F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) imaging for the staging of pathologically-confirmed breast cancer were included. The tumor SUVmax of each patient was calculated by 18F-FDG PET/CT. Serum YKL-40, ischemia modified albumin (IMA), carcinoembryonic antigen (CEA), and cancer antigen 15-3 (CA15-3) levels were assessed.. A group of 38 healthy women were included as controls, from which serum YKL-40 and IMA levels were obtained.
RESULTS: Compared to healthy subjects, serum YKL-40 and IMA levels were significantly higher in patients with breast cancer (p<0.001 for both). Patients with a tumor size of 2-5 cm had significantly higher YKL-40 (p=0.002), SUVmax (p=0.008), CEA (p=0.025), and CA15-3 (p=0.016) measurements than patients with a tumor size of <2 cm. However, IMA levels did not vary (p>0.05) between the two groups of tumor sizes. While YKL-40 showed significant correlations with CA15-3 (r=0.318, p=0.023) and IMA (r=0.257, p=0.016), no correlation was found between SUVmax and the measured serum variables in the breast cancer group (p>0.05).

DISCUSSION AND CONCLUSION: Our results indicate that serum IMA and YKL-40 levels were above average in breast cancer patients. Also, increasing SUVmax and serum YKL-40 levels may be separately observed related to tumor size. YKL-40 and SUVmax may be utilized in the evaluation and follow-up of breast cancer.