The Interleukin-12 Family Serum Levels (IL-12, IL-23, IL-27, IL-35, and IL-39) in Iraqi Females Breast Cancer Patients: A Case-Control Study

Breast cancer is the commonest cancer among women in Iraq and has a significant public health impact. Interleukin-12 family cytokines, along with interleukin-23 (IL-23), interleukin-27 (IL-27), and, more recently identified as a member of the family, interleukin 39 (IL-39) and interleukin 35 (IL-35), are essential for immune regulation and tumor–host interactions. To assess the serum IL-12 family cytokines in Iraqi women with breast cancer, and to explore their discriminatory value between patients and healthy controls. In the present case–control study, 400 serum samples of Iraqi female BC patients, as well as 100 normal age-matched and ethnicity-matched control sera, were tested by enzyme-linked immunosorbent assay for this purpose. Age group and grade comparisons were made. Receiver operating characteristic (ROC) curve exploratory analysis was performed within the same cohort. Breast cancer patients had significantly elevated levels of all of the IL-12 family cytokines in serum when compared with controls (p < 0.001). Cytokine levels were higher with a greater stage of tumor, but the levels did not differ according to age. The exploratory ROC analysis showed high apparent discrimination in this group, particularly for IL-35 and IL-39; however, it is important to interpret these estimates with caution due to the lack of independent validation. Serum IL-12 family cytokines may be indicative of the T-cell dysfunction that is associated with tumors of the breast. Although these cytokines appear to be of biological interest, their clinical value must be demonstrated in large-scale independent longitudinal studies with external validation and interval estimates.