Study challenges long-held idea about colorectal cancer
A new study finds metastatic colorectal cancer's immune defenses may begin outside the cancer cell, challenging view held for decades.
A recent study by researchers from the University of South Florida Health, Tampa General Hospital, and Hokkaido University in Japan challenges decades-old beliefs about metastatic colorectal cancer. Contrary to long-held views, the study reveals that the immune defenses against this type of cancer may originate from outside the cancer cells, in the tumor microenvironment.
This discovery, published in the Journal of Experimental & Clinical Cancer Research, could provide a new target for therapies aimed at improving outcomes for the world's second-leading cause of cancer-related deaths.
The research identified a previously unrecognized mechanism whereby elevated levels of sphingosine-1-phosphate (S1P), a lipid that promotes tumor growth, and decreased levels of ceramide, a cancer cell-killing lipid, create conditions that suppress immune responses and contribute to more advanced disease and poorer patient survival. Through laboratory experiments, the researchers blocked two key components of the pathway, allowing healthy killer T cells to once again successfully attack the cancer cells.
Traditionally, scientists believed that the "rheostat" model—where higher S1P levels trigger cancer growth and higher ceramide levels trigger cell death—occurred solely within cancer cells. However, the new study using advanced spatial mapping technology showed that this molecular balancing act actually takes place in the immune cells surrounding the tumor.
By examining 574 human colon cancer tissue samples, the researchers found that as colorectal cancer spreads, S1P levels in the surrounding healthy-looking support tissue and immune cells rise significantly, while ceramide levels drop.
This shift in lipid levels creates an ongoing inflammatory state that hinders the effectiveness of killer immune cells, making it difficult for them to reach and destroy the tumor. The study also uncovered a specific three-gene signature strongly linked to aggressive cancer, high patient mortality, and poor responses to standard immunotherapy drugs.
The findings suggest that targeting the S1P/S1PR3 pathway could potentially alter the immune environment surrounding a tumor, enhancing the efficacy of immunotherapies for advanced colorectal cancer patients.
Written by urgent.news from Futurity's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
