IRS2 and colorectal carcinoma: To further validate the hypothesis connecting IRS2 amplification with an increased risk of BM in CRC, we analyzed the MSK-MET tropism cohort,18 comprising 3,548 CRC samples from primary tumors (n = 2,401) and metastases (n = 1,147), including 22 BM samples (Supplementary Figure S1F).