# Identification of biomarkers in multiple myeloma: A comprehensive study combining microarray analysis and Mendelian randomization

## TL;DR

This study identifies myeloperoxidase (MPO) as a potential biomarker for multiple myeloma, linked to immune-related pathways and disease progression.

## Contribution

The study combines microarray analysis and Mendelian randomization to validate MPO as a causal biomarker for multiple myeloma.

## Key findings

- MPO was identified as a key hub gene with significant differences between MM patients and controls.
- Functional analysis linked MPO to immune-related pathways in MM.
- Mendelian randomization confirmed a causal relationship between MPO and MM risk.

## Abstract

Despite remarkable advancements in the treatment of multiple myeloma (MM), relapse remains a challenge. However, the mechanisms underlying this disease remain unclear. This study aimed to identify potential biomarkers that could open new avenues for MM treatment. Microarray data and clinical characteristics of patients with MM were obtained from the Gene Expression Omnibus database. Differential expression analysis and protein–protein interaction (PPI) network construction were used to identify hub genes associated with MM. Predictive performance was further assessed using receiver operating characteristic curves and nomogram construction. Functional enrichment analysis was conducted to investigate possible mechanisms. Mendelian randomization (MR) was used to evaluate the causal relationship between the crucial gene and MM risk. Topological analysis of the PPI network revealed five hub genes associated with MM, with myeloperoxidase (MPO) being the key gene owing to its highest degree and area under the curve values. MPO showed significant differences between patients with MM and controls across all datasets. Functional enrichment analysis revealed a strong association between MPO and immune‐related pathways in MM. MR analysis confirmed a causal relationship between MPO and the risk of MM. By integrating microarray analysis and MR, we successfully identified and validated MPO as a promising biomarker for MM that is potentially implicated in MM pathogenesis and progression through immune‐related pathways.