# Parallel Alterations in Gut and Tumor Microbiota in Pediatric Oncology: Potential Impacts on Disease Progression and Treatment Response

## TL;DR

This paper reviews how gut and tumor microbiota in children with cancer may affect disease progression and treatment outcomes, highlighting the need for more research.

## Contribution

The paper emphasizes the under-researched role of microbiota in pediatric oncology and calls for larger studies to understand its impact.

## Key findings

- Gut microbiota alterations influence tumor formation and treatment response in pediatric oncology.
- Tumor tissues are not sterile and contain microorganisms that can affect prognosis.
- Current data on pediatric populations are limited, especially for non-hematological cancers.

## Abstract

The correlation between the microbiota and tumor initiation and development has been widely studied over the past few years. Several studies have shown that alterations in the gut microbiota can influence the therapeutic efficacy of chemotherapy and immunotherapy against tumors. It was also indicated that the tumorous tissue was not sterile, as it contained various microorganisms. This niche plays a crucial role in tumor formation through different pathological signaling pathways. With this newly discovered knowledge, professionals in the future may focus not only on chemotherapy, immunotherapy, or radiotherapy, but also on restoring the healthy gut microbiota composition to help patients achieve better outcomes.

In the last decade, knowledge of gut microbiota has expanded. Several studies have demonstrated a correlation between certain diseases and alterations in gut microbiota. A comprehensive understanding of this complex ecosystem is still lacking; however, this review highlights the importance of microorganisms in oncology. Recently, several studies have demonstrated that the gut microbiota influences therapeutic efficacy and tumor formation, also known as tumorigenesis. We must remember that these microorganisms also play a crucial role in tumor prognosis. Since the discovery of Fusobacterium nucleatum in colorectal carcinoma (CRC), it has been established that tumor tissues are not sterile and contain microorganisms that can lead to either beneficial or harmful pathways, affecting tumor size and response to chemotherapeutic agents. Additionally, it should be noted that data on the pediatric population are limited, as this area has not been widely researched due to the low number of cases and the complexity of therapeutic approaches. In children, the only available data are mainly based on hematological malignancies, such as acute lymphoblastic leukemia (ALL). For a better understanding, larger cohorts are required.