Psychoneuroimmunology and breast cancer: IL-6 - a possible but complex biomarker

Abstract

Psychoneuroimmunology and breast cancer: IL-6 – a possible but complex biomarker Degree Project, Programme in Medicine Alexandra Leinonen Supervisor: Elisabeth Kenne Sarenmalm Research and Development, Skaraborg Hospital, Sweden, 2018 Key words: psychoneuroimmunology, breast cancer, IL-6, mood disorder. AbstractAbstract AbstractAbstractAbstract Background: Mood disorders are common in oncology patients and inflammation has been pointed out as a possible link between depression and cancer. The concentration of the cytokine IL-6 (Interleukin 6) has been showed to be increased in both depression and cancer. IL-6 is also correlated to overall survival in late stage cancer. This study investigates whether IL-6 correlates with symptoms of mood disorder, coping capacity, personal growth and common symptoms in women with breast cancer. Methods: Data from 205 women diagnosed with breast cancer was included in the study. IL-6 concentrations were determined in serum and symptoms of mood disorder, coping capacity and personal growth was measured using Hospital Anxiety and Depression Scale, Sense of Coherence Scale and Posttraumatic Growth Inventory respectively. The Memorial Symptom Assessment Scale was used to measure both psychological and physiological symptoms. The data was analyzed in SPSS with Spearman’s correlation coefficient and Mann-Whitney test. Patients with ongoing MDD (Major Depressive Disorder) were excluded. Results: IL-6 positively correlated to physiological symptoms in late stage as well as cancer progress which is in line with earlier studies. Of the psychological factors measured, positive correlations were found between IL-6 and coping capacity, and IL-6 and “Appreciation for Life” in the women with early stage breast cancer. Conclusion: Our results are in line with the idea that systemic IL-6 correlates with disease stage in breast cancer patients, but unlike earlier studies IL-6 does not correlate with symptoms of mood disorder. IL-6 might serve as a prognostic marker in more advanced stages of cancer but does not seem to have that function in earlier stages of breast cancer. A more refined understanding of how to best analyze the relations between our immune system and mood in cancer patients is desirable, as recent research have suggested: omicsbased systems biomedicine methods seem promising for the field of inflammation-depression research.