Adenocarcinomas make up 95 percent of all colorectal cancer cases. In the gastrointestinal tract, adenocarcinomas develop in the cells of the lining inside the colon and/or the rectum. They typically start as a growth of tissue called a polyp. A particular type of polyp, called an adenoma, may develop into cancer. Polyps are often removed during a routine colonoscopy before they may develop into cancer.
In the CMS4 mesenchymal subtype colon epithelial tumors, the PDGF-ß-receptor is typically over-expressed by stromal cells of mesenchymal origin. Tumor cells may also acquire PDGF-ß-receptor expression following epithelial-to-mesenchymal transition, which occurs during metastasis formation.
PDGF-ß-receptor expression in primary colon cancer is correlated with short disease-free and overall survival and the receptor likely contributes to the aggressive phenotype of colorectal tumors. For these frequent metastasizing, and therapy-resistant tumors, the radionuclide therapy with 177Lu-BOT501 is in development. Enrollment of the first patient in a clinical Proof of Concept imaging study is expected for 2021.