Heterogeneity of molecular alterations in CRC with peritoneal carcinomatosis

In a subset of patients with metastatic colorectal cancer (mCRC), the peritoneum is the predominant site of dissemination. While cure can be achieved by cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC), this procedure is associated with long-term morbidity and high relapse rates. In this episode of ModPath CHAT, Drs. Siesing and Jirstrom from Lund University in Sweden discuss their recent study in Modern Pathology on the topic. Multi-region immunohistochemical profiling and deep targeted DNA-sequencing was performed on 7 mCRC patients with peritoneal carcinomatosis (PC). SATB2 was lacking in the majority of cases, and a conspicuous intra-patient heterogeneity was denoted for expression of (RBM3). Mutations in key CRC driver genes, i.e., KRAS, APC and TP53, were homogenously distributed across all samples. The authors conclude that their findings should trigger additional studies addressing the potential distinctiveness of mCRC with PC, which might pave the way for improved personalized treatment of these patients.