Serum concentration of sex hormone-binding globulin in healthy volunteers and patients with breast cancer stratified by sex and age

The objective of the present study was to compare sex hormone-binding globulin (SHBG) levels according to sex (healthy male and female volunteers) and age to determine reference values. Serum SHBG expression levels in patients with breast cancer with different tumor burden states were also determined. A total of 109 samples were obtained from 34 patients in 3 different disease states (non-tumor, localized tumor and systemic metastasis) during follow-up. A sandwich ELISA was conducted to measure SHBG, cancer antigen (CA)15-3 and CA125 expression levels. Wilcoxon rank-sum tests were performed on non-normally distributed data and an unpaired t-test was used for normally distributed variables. SHBG expression levels were higher in females compared with males (P<0.0001). When SHBG expression levels were compared by sex, the difference was maintained in the age groups <30, 30-39 and >= 50 years, but not in the 40-49 years group. In males, SHBG expression levels increased until the age of 49 and then decreased (P=0.01). In females, SHBG expression levels exhibited a decreased trend until the age of 49 (P=0.66). In patients with breast cancer, the SHBG expression levels revealed a decreasing trend after the age of 50, which was different compared with the healthy females. There was a decreasing trend of SHBG expression levels from pre-menopause to post-menopause healthy volunteers (P=0.74). CA15-3 (r(2)=0.07; P=0.59) and CA 125 (r(2)=-0.18; P=0.17) levels did not exhibit any significant correlation with SHBG expression levels. There was a significant difference in the SHBG expression levels between male and female healthy volunteers. SHBG expression levels also revealed different patterns between healthy female volunteers and female patients with breast cancer >= 50 years of age. The present study demonstrated that SHBG does not have value as a biomarker, but different reference values according to age and sex may aid in predicting high-risk groups for hormone-dependent cancer and guide treatment direction for post-menopausal breast cancer.