Plasma cytokine profiles in breast cancer patients and their association with therapeutic response in Peru: a prospective cohort study

Background: Breast cancer (BC) is the most common malignant neoplasm in women worldwide and in Peru. Beyond hormonal and genetic factors, cytokines play a key role in tumor aggressiveness and therapeutic resistance. However, evidence on circulating cytokine profiles in Latin American populations is limited. Objective: We aimed to characterize the plasma cytokine profile in Peruvian women with BC and evaluate its association with molecular subtypes and treatment response. Materials and methods: A prospective cohort study was conducted. We included 88 BC patients with clinical stage II-III, who were diagnosed at three different cancer centers in Peru: Instituto Nacional de Enfermedades Neoplásicas (INEN, Lima-Peru), Instituto Regional de Enfermedades Neoplásicas del Norte (IREN-NORTE, Trujillo-Peru), and Instituto Regional de Enfermedades Neoplásicas del Sur (IREN-SUR, Arequipa-Peru). Plasma samples were obtained prior to any treatment being administered and underwent analysis using the Bio-Plex Pro™ Human Cytokine 48-Plex Screening Panel kit. Poisson regression models were used to evaluate the association between cytokine levels and complete pathological response (pCR) and clinical response. Results: Cytokine concentration differences in MIP-1β, IL-9, GRO-α, and TNF-β were observed between BC molecular subtypes. Furthermore, lower levels of circulating FGF BASIC appear necessary to increase the relative risk of achieving pCR (RR = 0.9779; 95% CI 0.9573-0.9989; p=0.0392). Decreased levels of FGF BASIC, PDGF BB, SDF-1, IL-12 P40, and IL-8 were also found to be related to an increased chance of clinical responses to treatments. Multivariable analyses indicated that only FGF-BASIC, PDGF-BB, and IL-12 P40 remained independently associated with clinical response. Conclusions: Our study identified plasma cytokines linked to BC subtypes and treatment response in a Peruvian cohort. FGF-BASIC consistently demonstrated a significant association with both pCR and clinical response.