Insight on BRAFV600E mutated colorectal cancer immune microenvironment

Abstract

Colorectal cancer (CRC) is the second deadliest malignancy for both sexes. The BRAF^V600E mutation, one of the most common driver mutations in CRC, is known for its poor prognosis due to the increased risk of metastasis. The effect of the BRAF^V600E mutation on the tumor microenvironment was the topic of the study reported in World Journal of Gastrointestinal Oncology, with special focus on immune status. The authors presented insightful findings that were exclusively based on macrophage polarity and cytokine levels, without investigating other relevant immune elements. A more comprehensive look into the dynamic immune activity of cancer environments will warrant more meaningful practical findings. In this letter, we discuss other significant immune factors and their possible implications on the tumor microenvironment of BRAF-mutated CRC.

Keywords: Colorectal cancer; BRAF^V600E; Tumor microenvironment; Microsatellite instability; Macrophages; Immune checkpoint proteins

Core Tip: The immune landscape of the tumor microenvironment is a crucial indicator of the proliferative and invasive activity of the tumor cells and serves as a predictor of response to targeted immunotherapeutic modalities. BRAF^V600E is one of the most common driver mutations in colorectal cancer thought to have a unique impact on the tumor immune microenvironment. It is unknown whether this impact is of a suppressive or activating nature. Future studies on larger samples, considering a wider array of immune elements, such as the infiltration of relevant immune cells as well as immune checkpoints’ expression, are needed.