Investigating the Microbiome and Volatile Organic Compound Profile of Children With Neuroblastoma

Background: Malignant tumors may lead to a catabolic state with loss of muscle and adipose tissue. The full picture of catabolism is termed cachexia and is associated with significant morbidity and mortality of cancer patients. Although the full picture is rarely observed up to 50% of children with cancer suffer from significant malnourishment. Additionally to tumor-induced catabolism, side-effects of chemotherapy may be problematic for the patients. In this regard up to 60% of children suffer from gastrointestinal mucositis presenting with nausea, vomiting, diarrhea or constipation and abdominal pain. In the worst case, mucositis may lead to bacterial translocation with life-threatening inflammatory response. Clinically this may require a reduction of the dosage or the number of chemotherapy cycles resulting in reduced effectivity. Up to now the therapy of mucositis is only symptomatic. Recent research of the applicant has shown a significant reduction of Lactobacilli in mice with neuroblastoma (a malignant childhood tumor). The dysbiosis was associated with catabolism, increased gut permeability and inflammation. Astonishingly, chemotherapy alone also leads to a significant reduction of Lactobacilli compared to sham mice, which may be linked to the development of mucositis clinically. Overall, the intestinal microbiome seems to play an essential role in the development of tumor-associated catabolism and chemotherapy-induced mucositis. Aim: The aim of this project is to determine if the changes in the intestinal microbiome observed in mice can also be seen in children with neuroblastoma. Methods: One part of the study will include 10 children with neuroblastoma (inclusion after verification of the diagnosis) and 10 healthy controls. The fecal microbiome will be determined by 16S-ribosomal deoxyribonucleic acid (rDNA) pyrosequencing. Volatile organic compounds in the breath will be sampled and measured by Gas Chromatography/Mass Spectroscopy. A basic science human