Abstract
Colorectal cancer (CRC) is a prevalent malignant tumour, with its incidence and mortality rates consistently ranking among the highest and exhibiting an upward trend. Extensive screening and early diagnosis are crucial for managing CRC progression and improving patient prognosis. This study aims to construct a novel analytical framework for integrating the sequencing data from tumour tissue and peripheral blood. By integrating and analysing the multi-omics data and clinical data from tumour tissues and peripheral blood, we confirmed that the LTB4R gene is significantly upregulated not only in tumour tissues but also in the peripheral blood of CRC patients. Further single-cell RNA sequencing (scRNA-seq) and immune cell correlation analyses revealed that Leukotriene B4 receptor 1 (LTB4R) is primarily expressed in macrophages, T cells, and other immune cells, with a significant negative correlation observed with M1-type macrophages, suggesting its potential pro-tumourigenic role in CRC by suppressing M1 macrophage. Additionally, simulated gene knockout analysis (scTenifoldKnk) demonstrated that LTB4R knockout significantly impacts immune-related pathways, including immune response and immune receptor activity. These findings not only highlight the potential of LTB4R as a peripheral blood diagnostic marker for CRC but also elucidate its involvement in tumour progression, offering novel insights for early clinical diagnosis and tumour screening systems.