Myeloid derived-suppressor cells in healthy women and in advanced breast cancer patients
Authors: N. Palazón Carrión, M.L. Sánchez León, C. Jiménez Cortegana, F.J. Valdivia García, I. Araujo Fernández, F. Henao Carrasco, M.A. Nieto García, V. Sánchez Margalet, L. de la Cruz Merino
Journal: Annals of Oncology (2019)

Background: In advanced breast cancer (ABC) some studies suggest a deleterious effect on survival when high levels of myeloid-derived suppressor cells (MDSC)1,2 are detected in peripheral blood. Furthermore, classical therapies like anthracyclines or gemcitabine seem to exert an immunostimulating effect by eliminating and/or altering the function of MDSC3. The objective of this study is to analyze the evolution of blood MDSC in patients with ABC prior to the standard first-line systemic therapy according to Clinical Practice Guidelines. Methods: MDSC levels are measured at three timepoints: basal, and after 2 and 6 months from first line systemic therapy onset. Data are compared the measurements obtained from the MDSC of a control group of healthy women. In addition, MDSC levels are monitorized and correlated with clinical outcomes in terms of overall response rate [clinical benefit (CB, complete response + partial response + stabilization lasting more than 24 weeks) versus (vs.) progression of disease (PD)]. Results: A total of 39 patients with ABC (34 CB, 5 PD) and 20 healthy women have been analyzed. 34 out of 39 patients were considered to obtain CB and 5 patients (12,82%) had PD as best response. Basal MDSC levels were higher in ABC patients prior to initiate any systemic therapy vs healthy population (p < 0,001). The levels of MDSC decreased sharply in those patients with CB (p 0,001), reaching statistical significance. However, no statistically significant differences were found in patients with PD (p 0,317) with respect to basal levels of MDSC (Table). Conclusions: Basal MDSC levels are higher in patients diagnosed with ABC compared to the healthy population. Systemic therapy seems to decrease the levels of blood MDSC of patients with ABC, which may eventually help to restore a better immunosurveillance profile in ABC patients that could impact on clinical evolution. Legal entity responsible for the study: The authors. Funding: Andalusian Public Progress and Health Foundation. Disclosure: All authors have declared no conflicts of interest. Table59P Evolution of the MDSC according to clinical response in ABC and basal MDSC in healthy cohortMDSC_Basal (mean)MDSC_Cycle_3 (mean)MDSC_Cycle_6 (mean)P valuePD ABC25,97 (95% CI: 6,47-45,47)5,38 (95% IC: 4,05-6,71)1,79*There is only one patient analyzed in cycle 6 with PD. DP, progression of disease; CB, clinical benefit; ABC, advanced breast carcinoma; MDSC, myeloid-derived suppressor cells; 95% CI, 95% confidence interval.0,317CB ABC13,03 (95% CI: 7,24-18,83)3,90 (95% IC: 2,56-5,23)2,98 (95% IC: 1,99-3,98)0,001Healthy cohort0,81 (95% CI: 0,52-1,10)––<0,001* There is only one patient analyzed in cycle 6 with PD. DP, progression of disease; CB, clinical benefit; ABC, advanced breast carcinoma; MDSC, myeloid-derived suppressor cells; 95% CI, 95% confidence interval. Open table in a new tab