Immacolata Cantiello

Interleukin-6 (IL-6) is a multifunctional cytokine with an essential role in immunity, inflammation, and cancer. Produced by immune, stromal and epithelial cells in response to infection or tissue stress, IL-6 regulates immune responses, acute-phase proteins (including serum amyloid A and C-reactive protein), hematopoiesis, and tissue remodeling. These effects are mediated via classical and trans-signaling pathways, which activate key intracellular cascades such as JAK/STAT3, MAPK, and PI3K/AKT. Accumulating evidence implicates dysregulated IL-6 signaling in both oncologic and infectious diseases, where it contributes to disease progression, immune evasion, and therapeutic resistance. This review aims to critically examine the role of IL-6 as a biomarker and therapeutic target in these two major clinical contexts: in cancer, IL-6 levels reflect tumor burden, prognosis, and therapy resistance in both adult and pediatric patients; in infectious diseases, circulating IL-6 may support early diagnosis and risk stratification, particularly in vulnerable pediatric populations. By integrating molecular mechanisms with clinical evidence, this review highlights IL-6 as a unifying biomarker linking inflammation, infection, and malignancy. It also addresses current limitations, including assay variability, lack of standardized reference ranges, especially in children, and challenges in clinical implementation.

Acute lymphoblastic leukemia (ALL) is the most common pediatric cancer, comprising almost 25% of all malignancies diagnosed in children younger than 20 years, and its incidence is still increasing. ALL is a blood cancer arising from the unregulated proliferation of clonal lymphoid progenitor cells. To make a diagnosis of B-cell ALL, bone marrow morphology and immunophenotyping are needed; cerebrospinal fluid examination, and chromosomal analysis are currently used as stratification exams. Currently, almost 70% of children affected by B-cell ALL are characterized by well-known cytogenetic abnormalities. However, the integration of results with “omic” techniques (genomics, transcriptomics, proteomics, and metabolomics, both individually and integrated) able to analyze simultaneously thousands of molecules, has enabled a deeper definition of the molecular scenario of B-cell ALL and the identification of new genetic alterations. Studies based on omics have greatly deepened our knowledge of ALL, expanding the horizon from the traditional morphologic and cytogenetic point of view. In this review, we focus our attention on the “omic” approaches mainly used to improve the understanding and management of B-cell ALL, crucial for the diagnosis, prognosis, and treatment of the disease, offering a pathway toward more precise and personalized therapeutic interventions.